[GITEA] add new gitea service (release/languages) (#9781)

* add gitea service based on gitlab

* update gitea to use mocks

* add gitea release test

* move tests to use public repo on codeberg and fixes

* add pagination, update tests to live, set gitea_url as required

* add auth test (wip)

* fix base auth test

* fix required optionalUrl, remove default, assume semver from firstpage

* update example to use stable repository

doc/server-secrets.md

@@ -167,6 +167,15 @@ These settings are used by shields.io for GitHub OAuth app authorization
 but will not be necessary for most self-hosted installations. See
 [production-hosting.md](./production-hosting.md).
 
+### Gitea
+
+- `GITEA_ORIGINS` (yml: `public.services.gitea.authorizedOrigins`)
+- `GITEA_TOKEN` (yml: `private.gitea_token`)
+
+A Gitea [Personal Access Token][gitea-pat] is required for accessing private content. If you need a Gitea token for your self-hosted Shields server then we recommend limiting the scopes to the minimal set necessary for the badges you are using.
+
+[gitea-pat]: https://docs.gitea.com/development/api-usage#generating-and-listing-api-tokens
+
 ### GitLab
 
 - `GITLAB_ORIGINS` (yml: `public.services.gitlab.authorizedOrigins`)