Remove postgis_tiger_geocoder and address_standardizer from the PostGIS code base

[Regina Obe]

I'd like to remove postgis_tiger_geocoder and address_standardizer from the
PostGIS code base and spin those off as separate project repos.
They would be still under the postgis gitea org, just not in PostGIS repo.

The reasoning is this.

1) They don't really use the PostGIS regress/install machinery.  They use
the PostgreSQL regress and make installcheck
2) The cycle at which we change these is different.
a) postgis_tiger_geocoder changes whenever census data changes, so doesn't
make sense to follow PostGIS release cycle. It also is all plpgsql code and
doesn't use any of the newer functions of PostGIS so can work with pretty
much any postgis version
b) address_standardizer has no dependence what so ever on PostGIS core and
the release cycle is much less frequent than postgis proper.


How badly will this mess up work of packagers?

I'm thinking doing this for the PostGIS 3.7 cycle.

Thanks,
Regina