[wip/py-sot-application] Cleanup and fix a few configure issues

* Rename to py-sot-application, as this is a python package. Properly
  preprend PKGTAG.python everywhere. Add conflicts on the previous package
  name.
* Add missing dependency on py-sphinx
* Pass SPHINX_BUILD program name to cmake
* Point MASTER_SITES to the official github distribution site
* Change CATEGORY to scripts
* Add a HOMEPAGE
* Fully define SYSTEM_SEARCH, looking for headers, python files and .pc

Bump PKGREVISION