Need triggering from simrel -> epp builds

[jonahgraham]

With the refactoring done in #120 the old way of triggering no longer works. We are dependent on resolution of https://gitlab.eclipse.org/eclipsefdn/helpdesk/-/issues/4359 before we can fully resolve this.

[jonahgraham]

In the absence of a triggering solution, I have marked EPP to run daily overnight and send emails on failed builds in #147

FYI: @merks feel free to add yourself to email recipients if it would help you

[merks]

@jonahgraham

I wondered if we might parameterize the job where the staging repo is the default value of the parameter, and when it's time to build against a specific promoted simrel repo, the appropriate uRL could be pasted into the text parameter field?

[jonahgraham]

It used to be that way, but I changed it couple of years ago so that the git repo would be reproducible for published builds. It also used to be that we would build the EPP from the simrel staging p2 repo all the time, because it used to be that Simrel would be disabled while EPP was running.

It would be nice to automate some of this, but I would like to see it be git commits not transient variables.

[jonahgraham]

Based on comments in #147 I added a comment to https://gitlab.eclipse.org/eclipsefdn/helpdesk/-/issues/4359#note_2182943 and am reopening this to see if we can get better triggers.