Description of problem:

With https://github.com/theforeman/foreman_maintain/commit/3a2fa00e5d8363f6896507303c1487a6f5b76f8e there is no more way to re-run a phase of an upgrade (or update) that was already run.

The removal of --phase was intentional, but I think it would be beneficial to be able to force the re-execution of the whole scenario.

If we decide not to implement a fix, we should at least remove the mention of --phase from the output of the upgrade runner:

% git grep -- --phase
README.md:          [--phase=phase TARGET_VERSION]      Run just a specific phase of the upgrade
lib/foreman_maintain/upgrade_runner.rb:          To enforce to run the phase, use `upgrade run --phase #{skipped_phase}`

How reproducible:

100%

Is this issue a regression from an earlier version:

"intentional" regression?

Steps to Reproduce:

1. run an upgrade that fails somewhere (e.g. in the installer)

2. re-run the upgrade

Actual behavior:

Running Procedures before migrating
================================================================================
Skipping pre_migrations phase as it was already run before.
To enforce to run the phase, use `upgrade run --phase pre_migrations`

Expected behavior:

Either there is a working way to re-run the phase, or the text should be removed.

Business Impact / Additional info: