Installing the Management utilities used to be pretty brute-force
operation which copied more or less everything over blindly and then
tried to remove what shouldn't be installed. This is clearly not a
terribly clean and sustainable solution, as subsequent issues with
it has proven (editor savefiles, patch .rej/.orig files etc were
routinely copied and never purged etc).

This takes a first stab at turning installation of gpMgmt/bin, sbin
and doc into proper recursive make targets which only install the
files that were intended to be installed.

Discussion: https://github.com/greenplum-db/gpdb/pull/8179
Reviewed by Bradford Boyle, Kalen Krempely, Jamie McAtamney and
many more