Use custom runner image with jq, kustomize, docker pre-installed

Build a runner-image based on node:20-bookworm with all CI tools
baked in, avoiding apt-get install in every workflow run. Runner
labels now point to gitea.coreworlds.io/lazorgurl/runner-image.

.gitea/workflows/ci.yaml

@@ -20,8 +20,6 @@ jobs:
         with:
           fetch-depth: 0
 
-      - run: apt-get update && apt-get install -y jq
-
       - name: Detect changed apps
         id: filter
         run: |

.gitea/workflows/deploy-preview.yaml

@@ -10,11 +10,6 @@ jobs:
     steps:
       - uses: actions/checkout@v4
 
-      - name: Install tools
-        run: |
-          apt-get update && apt-get install -y jq curl
-          curl -sL https://github.com/kubernetes-sigs/kustomize/releases/download/kustomize%2Fv5.6.0/kustomize_v5.6.0_linux_amd64.tar.gz | tar xz -C /usr/local/bin
-
       - run: corepack enable && corepack prepare pnpm@latest --activate
 
       - run: pnpm install --frozen-lockfile

.gitea/workflows/deploy-production.yaml

@@ -12,11 +12,6 @@ jobs:
         with:
           fetch-depth: 2
 
-      - name: Install tools
-        run: |
-          apt-get update && apt-get install -y jq curl
-          curl -sL https://github.com/kubernetes-sigs/kustomize/releases/download/kustomize%2Fv5.6.0/kustomize_v5.6.0_linux_amd64.tar.gz | tar xz -C /usr/local/bin
-
       - run: corepack enable && corepack prepare pnpm@latest --activate
 
       - run: pnpm install --frozen-lockfile