[Chore] Add custom CI Docker image with Node.js 24, pnpm 10, and uv (#268)

This is meant to drastically speed up CI because it skips the lengthy installation.

Co-authored-by: jebus <lorsbach@envipath.com>
Reviewed-on: enviPath/enviPy#268
Co-authored-by: Tobias O <tobias.olenyi@envipath.com>
Co-committed-by: Tobias O <tobias.olenyi@envipath.com>

.gitea/workflows/build-ci-image.yaml

@@ -0,0 +1,48 @@
+name: Build CI Docker Image
+
+on:
+  workflow_dispatch:
+  push:
+    branches:
+      - develop
+      - main
+    paths:
+      - '.gitea/docker/Dockerfile.ci'
+      - '.gitea/workflows/build-ci-image.yaml'
+
+jobs:
+  build-and-push:
+    runs-on: ubuntu-latest
+    steps:
+      - name: Checkout repository
+        uses: actions/checkout@v4
+
+      - name: Set up Docker Buildx
+        uses: docker/setup-buildx-action@v3
+
+      - name: Log in to container registry
+        uses: docker/login-action@v3
+        with:
+          registry: git.envipath.com
+          username: ${{ secrets.CI_REGISTRY_USER }}
+          password: ${{ secrets.CI_REGISTRY_PASSWORD }}
+
+      - name: Extract metadata
+        id: meta
+        uses: docker/metadata-action@v5
+        with:
+          images: git.envipath.com/envipath/envipy-ci
+          tags: |
+            type=raw,value=latest
+            type=sha,prefix={{branch}}-
+
+      - name: Build and push Docker image
+        uses: docker/build-push-action@v5
+        with:
+          context: .
+          file: .gitea/docker/Dockerfile.ci
+          push: true
+          tags: ${{ steps.meta.outputs.tags }}
+          labels: ${{ steps.meta.outputs.labels }}
+          cache-from: type=registry,ref=git.envipath.com/envipath/envipy-ci:latest
+          cache-to: type=inline