Add all direct dependencies.

Signed-off-by: David Runge <dvzrv@archlinux.org>

Signed-off-by: David Runge <dvzrv@archlinux.org>

Signed-off-by: David Runge <dvzrv@archlinux.org>

Since coverage 6.4 and Python 3.11 tomli is no longer a hard dependency
as Python itself provides a toml library.

Removing the tests for python2-coverage as they would require packaging python2-hypothesis again.
Simplifying the source directory handling (copying is not required, as the interpreters can
build and test next to one another just fine).
Skip build when installing in package_*().
Adding python{,2}-setuptools to depends as the packages have entry_points.
Adding python{,2}-toml as optdepends for pyproject.toml support.