Container image containing doc-utils

## Example use in Actions

```yaml
name: Build docs

on:
  push:
    branches:
    - master

jobs:
  build:
    runs-on: ubuntu-latest
    container:
      image: gitea.jbrumond.me/doc-utils/utils:0.2
    steps:
    - name: Check out the repo
      uses: actions/checkout@v3
      
    - name: Build docs to webpage
      run: docs2website ./config.yaml
```