- build markdown/HTML versions, use separate makefile targets/hecat configuration files for each export format/push task
- add non-free.md generation step to markdown export hecat configuration file
- add makefile targets to push exports to https://github.com/awesome-selfhosted/awesome-selfhosted and https://github.com/nodiscc/awesome-selfhosted-html-preview
- install: install sphinx <7 directly using pip since it can't be installed from setup.py https://github.com/sphinx-doc/sphinx/issues/11130
- pin sphinx to version <7, sphinx-design is not compatible with sphinx 7 https://github.com/executablebooks/sphinx-design/issues/130
- add sphinx configuration file
- tools/makefile: monkeypatch furo theme to display build tools and license link in footer (furo/sphinx does not provide a way to customize this https://github.com/pradyunsg/furo/discussions/612)
- fix dependencies between makefile targets
- setup/document SSH deploy keys usage
- each repository requires a different deploy key, trying to add a deploy key to repo B, which has already been added to repo A results in error 'this key already exists'
- set git remote URL to use ssh URIs before push (required to use SSH deploy keys)
- when referencing an environment secret, environment: key must be defined explicitly for the step (https://docs.github.com/en/actions/deployment/targeting-different-environments/using-environments-for-deployment#referencing-an-environment)
- use a single SSH key file/no ssh-agent, else git push will try to use the first registered key and fail with permission denied when trying to push to the HTML repository
- use variables to identify target repos
- use temporary repositories as push destination
- ref. #3558
- `https://uguu.se/ : HTTPSConnectionPool(host='uguu.se', port=443): Max retries exceeded with url: / (Caused by NewConnectionError('<urllib3.connection.HTTPSConnection object at 0x7efd0c418970>: Failed to establish a new connection: [Errno 111] Connection refused'))`
