enable python bindings by default

change ci yml since python bindings now on by default

still need flag DUNE_RUNNING_IN_CI which is now turned on by default in CI config.opts file - this is used to set the index url to the gitlab registry for package download

test both turing of bindings and turning off python altogether in CI

make sure embeded test does not cause testing to fail if dune package could not be installed - this is not a perfect solution but works for now

exclude dune.src_dir from module load since this is a link set by cmake