Blag

* Ignore FileNotFoundError when trying to get the last modified time of files
in directories. This happens for example with temporary emacs files.
* Added changelog to docs
* removed ruff's target-version from pyproject.toml, this value defaults to the
projects requires-python

* added manpage
* added makefile target for generating blog's manpage
* added makefile target for serving blags docs locally
* mkdocs: disabled loading of google fonts, using locally installed system
fonts instead
* Debian: simplified html docs directory for blag-doc package
* Debian: changed section from Python to Web
* updated dependencies

* fixed devsever so it does not crash anymore when the (re-)build fails
* dropped support for Python 3.8 and 3.9
* updated dependencies

* fixed `suggests` to blag-doc

* switched from flake8 to ruff
* added missing docstrings
* fixed dev requirements in pyproject, still pointing to sphinx
* added Python3.12 to test suite
* removed debian/watch

* default theme: `img` have now `max-width: 100%` by default to avoid very
large images overflowing
* packaging: explicitly list `templates`, `static` and `content` as packages
instead of relying on package-data for setuptools. additionally, created a
MANIFEST.in to add the contents of these directories here as well. the
automatic finding of namespace packages and packaga-data, currently does not
work as advertised in setuptools' docs
* updated dependencies
* created debian/watch