[MacPorts] #71578: port selfupdate: Print warning when port sync is delayed

[MacPorts]

#71578: port selfupdate: Print warning when port sync is delayed
----------------------------+---------------------
 Reporter:  Dave-Allured    |      Owner:  admin@…
     Type:  enhancement     |     Status:  new
 Priority:  Normal          |  Milestone:
Component:  server/hosting  |    Version:
 Keywords:                  |       Port:
----------------------------+---------------------
 There are recent incidents of many hours unexpected delay to port sync.
 The expected delay is only **30 minutes** according to
 [https://github.com/macports/macports-
 infrastructure/blob/master/jobs/README this README].

 For example: https://trac.macports.org/ticket/71541

 It would be helpful to print an appropriate warning message when this is
 happening, for tasks such as `port selfupdate`.  This would warn users
 that they might be missing the latest port updates, and that the system is
 just slow, not broken.  The message should include the UTC time of the
 actual last update, number of minutes or hours currently delayed, and a
 guideline for what is an excessive delay before reporting.

-- 
Ticket URL: <https://trac.macports.org/ticket/71578>
MacPorts <https://www.macports.org/>
Ports system for macOS