feat: migrate to Gitea Actions with shared release workflow

.gitea/workflows/Release.yml

@@ -0,0 +1,9 @@
+name: Release
+
+on:
+  push:
+    branches: [main]
+
+jobs:
+  release:
+    uses: unboundsoftware/shared-workflows/.gitea/workflows/Release.yml@main

.gitlab-ci.yml

@@ -1,15 +0,0 @@
-include:
-- template: 'Workflows/MergeRequest-Pipelines.gitlab-ci.yml'
-- project: unboundsoftware/ci-templates
-  file: Defaults.gitlab-ci.yml
-- project: unboundsoftware/ci-templates
-  file: Release.gitlab-ci.yml
-
-stages:
-- build
-
-build:
-  stage: build
-  image: amd64/alpine:3.23.2@sha256:f276aafd5da0d02877540e1dbf42bdd6b08191073438dd03f0d3b8078f30fb34
-  script:
-  - env | sort