Add support for custom templates in rb-site.

Review Request #11376 — Created Jan. 12, 2021 and submitted

Review Board

We've had a long-standing request from a customer to allow the template to be customizable via a template. This
change enables this through a --settings-local-template parameter,
which can point to a local file that will be processed and turned into
the resulting

The help output displays the default template file we use, so that
consumers can better find something to base theirs off of.

Other templates are not (at this time) customizable, though we could now
more easily do this in the future. Most of our templates are for web
servers or cron, rather than part of the Review Board runtime, and are
therefore less critical for the site installation.

Tested with and without a custom template. Saw the expected result in
each case.

Add support for custom templates in rb-site.
  1. Ship It!
Review request changed

Status: Closed (submitted)

Change Summary:

Pushed to release-4.0.x (d282286)