Remove pg_top_compile and pg_top related env variables

Compilation and development of pg_top can be done locally as its code
is really simple, so let's stick with that for development.
Remove pgodbc_compile and pgodbc related env variables

Compilation and development of pgodbc can be done locally as its code
is really simple, so let's stick with that for development. Configure
can be kicked for example only once and then reused all the time.