Use converted (plain) SVGs with paths instead of texts

Signed-off-by: David Runge <dave@sleepmap.de>

book/source/04-certificates.md

@@ -49,7 +49,7 @@ An {term}`OpenPGP certificate` (or "{term}`OpenPGP key`") is a collection of an
 
 This documentation collectively refers to {term}`component keys<OpenPGP Component Key>` and {term}`identity components<Identity Component>` as "the {term}`components<Component>` of a {term}`certificate<OpenPGP Certificate>`."
 
-```{figure} diag/Components_of_an_OpenPGP_Certificate.svg
+```{figure} diag_converted/Components_of_an_OpenPGP_Certificate.svg
 :name: fig-openpgp-certificate-components
 :alt: Depicts a box with white background and the title "OpenPGP certificate". In the box several other boxes and accompanying texts, representing component keys and User IDs, are shown. There are three component keys boxes with a green frame, each with a dotted lower-left section, that shows the text "key creation time" and the green public key symbol in the lower right area. All three have a title, a unique fingerprint below the box and a unique capability keyword, perpendicular to the box on the right side. The top-most component key box has a light-green background, with the title "Component Key (primary)" and capability keyword "certification". The second-to-top component key box has a white background, with the title "Component Key" and capability keyword "encryption". The lowest component key box has a white background, with the title "Component Key" and capability keyword "signing". There are two User ID boxes, each with a black frame, open to top left and lower right corner. Both boxes have a user icon on the top left side, the title "User ID" on the top right side and a User ID string at the bottom. The top box has "Alice Adams <alice@example.org>" and the lower box has "Alice" as User ID string.
 
@@ -85,7 +85,7 @@ An {term}`OpenPGP component key`
 
 Each {term}`OpenPGP component key` possesses an *{term}`OpenPGP fingerprint`*. This {term}`fingerprint<OpenPGP Fingerprint>` is derived from the {term}`public key material<OpenPGP Certificate>`, the {term}`creation timestamp<Creation Time>`, and, when relevant, the ECDH parameters.
 
-```{figure} diag/Fingerprint.svg
+```{figure} diag_converted/Fingerprint.svg
 :name: fig-fingerprint
 :alt: Depicts a box with white background and the title "Fingerprint of an OpenPGP component key." Inside, another box with a green frame, the title "Component Key", the text "key creation time" on the lower left and a the green public key symbol on the lower right is shown. Below the component key box a fingerprint in a box with a light-yellow background and a yellow dotted line is depicted. The word "Fingerprint" is shown left of the box with the fingerprint and both are connected with a yellow dotted line.
 

book/source/05-private.md

@@ -18,7 +18,7 @@ This chapter is about the remaining counterpart to the elements of certificates:
 
 In this book, we treat the private key material as logically separate from the OpenPGP certificate. A separate subsystem typically handles operations that use private key material. It is useful to think about OpenPGP certificates on one hand, and the associated private key material, on the other, as related but separate elements[^pkcs11]:
 
-```{figure} diag/OpenPGPCert_with_privatekeystore.svg
+```{figure} diag_converted/OpenPGPCert_with_privatekeystore.svg
 :name: fig-openpgp-certificate-with-private-key-store
 :alt: Depicts a diagram on white background with an OpenPGP Certificate and a private key store. Gray dotted lines connect the green public key symbols of the OpenPGP Certificate with red dotted private key symbols in the private key store.
 
@@ -33,7 +33,7 @@ However, there is one exception. The cryptographic private key material is somet
 
 Sometimes it is useful to handle OpenPGP certificates combined with private key material in the form of [*transferable secret keys (TSK)*](https://www.ietf.org/archive/id/draft-ietf-openpgp-crypto-refresh-11.html#name-transferable-secret-keys). Transferable secret keys are a serialized format that combines OpenPGP certificate data with the connected private key material, stored in a single file.
 
-```{figure} diag/TSK.svg
+```{figure} diag_converted/TSK.svg
 :name: fig-transferable-secret-key
 :alt: Depicts a box on white background with the title "Transferable secret key". It is identical to the figure depicting an OpenPGP certificate, with the exception, that in each component key box, below the green public key symbol, also the red dotted private key symbol is shown.
 

book/source/18-zoom_certificates.md

@@ -77,7 +77,7 @@ This version of Alice's certificate contains just two packets:
 
 This is the shape of the packets we'll explore in the subsequent sections:
 
-```{figure} diag/Minimal_OpenPGP_certificate.svg
+```{figure} diag_converted/Minimal_OpenPGP_certificate.svg
 :name: fig-public-certificate-minimal
 :alt: TODO
 
@@ -365,7 +365,7 @@ The hash digest is calculated from the following data (see [Computing Signatures
 
 The signature is calculated from this hash digest.
 
-```{figure} diag/direct_key_signature_packet.svg
+```{figure} diag_converted/direct_key_signature_packet.svg
 :name: fig-direct-key-signature-packet
 :alt: Depicts a box with white background, title "Signature packet" and subtitle "Direct Key Signature (type ID 0x1F)". In the center a box with white background and yellow frame is shown. Inside it several items are listed, separated by yellow dotted horizontal lines. The first three are "Version", "Public-Key Algorithm" and "Hash Algorithm". The fourth item is called "Hashed area" and confines further sub-items by a light-yellow frame on the top and left side. The sub-items are "Signature Creation Time", "Key Expiration Time", "Preferred Symmetric Ciphers for v1 SEIPD", "Preferred Hash Algorithms", "Key Flags", "Features" and "Issuer Fingerprint". The fifth item is named "Unhashed area" and again introduces an area for sub-items, this time using a light-gray border on the top and left side. The unhashed area has no sub-items though. The last item is called "Cryptographic Signature", with the subtitle "by the primary key over primary key, subkey and signature metadata" and includes the green cryptographic signature symbol on the right side.