Replace GitLab integration with Gitea in issue reporting

Migrated issue reporting functionality from GitLab to Gitea. Updated environment variables, dependencies, and configuration references to support Gitea. Introduced `GiteaClient` for communication with the Gitea API and refactored related code and tests to align with the new integration.

docs/utilities-and-bootstrap.md

@@ -84,7 +84,7 @@ An example configuration file is `bot.properties.example`. Key configuration val
 | `NETNEUTRALITY_API_PORT`                                                           | Port for the [Web API](web-api.md) (default `9000`).                                            |
 | `MYSQL_*`                                                                          | Database connection settings (see [persistence.md](persistence.md)).                            |
 | `NETNEUTRALITY_SENTRY_DSN`                                                         | Enables Sentry when present.                                                                    |
-| `GITLAB_HOST` / `GITLAB_TOKEN` / `GITLAB_PROJECT_ID`                               | GitLab issue reporting ([`ReportIssueTask`](tasks.md#worked-example--gitlab-bug-report-modal)). |
+| `GITEA_HOST` / `GITEA_TOKEN` / `GITEA_OWNER` / `GITEA_REPO`                        | Gitea issue reporting ([`ReportIssueTask`](tasks.md#worked-example--gitea-bug-report-modal)). Token needs `write:issue`. |
 | `NETNEUTRALITY_LAVALINK_URI` / `_PASSWORD` / `_NAME`                               | Connection settings for the [Lavalink node](music.md#settings).                                 |
 | `NETNEUTRALITY_PO_TOKEN` / `NETNEUTRALITY_VISITOR_DATA` / `NETNEUTRALITY_CIPHER_*` | YouTube auth/cipher settings, consumed by the node via `lavalink/application.yml`.              |