sysrepo: Remove Lua bindings, build Python bindings in separate package

sysrepo: Remove Lua bindings, build Python bindings in separate package

This change:

* Removes building of Lua bindings. These bindings were already removed
  upstream[1].

* Fixes building of Python bindings:
  * Fix SWIG_DIR path (note that SWIG_VERSION will need to be updated
    whenever the swig package is upgraded)
  * Fix Python module paths and filenames

* Packages the Python bindings in a new package (python3-sysrepo) and
  builds it by default, instead of depending on a config option.

[1]: https://github.com/sysrepo/sysrepo/pull/1429

Signed-off-by: Jeffery To <jeffery.to@gmail.com>