[MacPorts] #54056: MacPorts should warn when not using "macports" rsync module

[MacPorts]

#54056: MacPorts should warn when not using "macports" rsync module
------------------------+-------------------
 Reporter:  ryandesign  |      Owner:
     Type:  defect      |     Status:  new
 Priority:  Normal      |  Milestone:
Component:  base        |    Version:  2.4.1
 Keywords:              |       Port:
------------------------+-------------------
 MacPorts currently prints this warning:

 {{{
 Warning: MacPorts is configured to use an unsigned source for the ports
 tree. Please edit sources.conf and change
 'rsync://rsync.macports.org/release/ports/' to
 'rsync://rsync.macports.org/release/tarballs/ports.tar'.
 }}}

 This advice is not optimal: the user should be advised to change it to
 "rsync:// rsync.macports.org/'''macports/'''release/tarballs/ports.tar".

 In addition to warning when not using a tarball, as was already done in
 [bebd94ad0415b859b37a9887dfae102b45e70590/macports-base], we should warn
 when not using the "macports" rsync module. (Using the old standalone
 "release" and "trunk" modules is deprecated; our new rsync server provider
 would like for us to wean users off of those old modules so that they can
 eventually remove them.)

 We currently issue this warning for all *rsync.macports.org hostnames, but
 not all of our mirrors use the same rsync module naming convention which
 complicates things. Ideally we would ask our mirror providers to change
 their setup to match ours. But until that happens, maybe we can only issue
 the rsync module name warning when using the official rsync.macports.org
 server and not when using a mirror.

--
Ticket URL: <https://trac.macports.org/ticket/54056>
MacPorts <https://www.macports.org/>
Ports system for macOS