Weed out, clarify Git ignore file
`data` has files ignored not only in `./data` but also in
`./script/data`, so change it to `/data`.
Adjust to renamed config file
Remove tox usage
Tests are run on Travis CI separately for different Python versions.
tox does not seem to provide an advantage here, so remove it to avoid
the installation overhead.
I think this is a good idea to avoid getting your own configuration files into the git.
Ignore path `.pytest_cache`
Ported tests from nose2 to pytest
Ignore mypy's cache directories
Ignore the `.cache/` path regarding version control
Moved everything from `webapp/` one level up and removed the directory.
Set up Sphinx-based documentation framework.
Moved OpenSSL keys for development server into a subdirectory and ignored its content.
Ignore virtual environment folders everywhere.
Ignore user data directory.
Initial population with basic layout/styling, a user system with authentication, a basic test setup and various utilities.