temporarily locking to latest version of Sphinx. Will downgrade once stable.
Additionally, removed anything I don't need at the moment. Copied this from an
old theme of mine.
Now, the HTML theme build is daisy-chained to the build of the Sphinx theme,
including a skeleton for watching, which will be part of user-acceptance
testing, which will be sphinx-autobuild building `docs/`.
Sphinx is part of the dependency defined in pyproject.toml, therefore redundant
to explicitly define it in Pipfile, since the project is an editable dependency.
Adding pipenv as a dependency to the pipenv environment itself is admittedly
counter-intuitive, however this gives the advantage of being able to install all
dependencies (including dev-dependencies) via the common and generally available
`pip` package manager interface. The generation of requirements.txt and
requirements-dev.txt is abstracted through the Makefile.
Since the repository is an older attempt at formulating a reference (it was more
of a failed boilerplating attempt). I (just) need to rearrange a couple of
things before being able to integrate the HTML theme reference.
