Add python_provide macros for all python3 rpm

This MR adds the folllowing definitions for all of the python%{python3_pkgversion} packages:

%{?python_provide:%python_provide python%{python3_pkgversion}-%{basename_}}

This automatically effectively adds Provides: python3-%{basename_} to these packages such that python36-ldas-tools-framecpp can be referenced just as python3-ldas-tools-framecpp. This only really impacts SL7 since all python3 packages on rocky 8 are just called python3- in the first place.