`supervisorctl tail` is not the most reliably way to get logs for the latest change detection and has been known to be fragile in the past.

We can instead read the full log for the service directly with `tac` and `sed` to extract all log content since the last change detection.

Common asserts have also been extracted out into separate methods.

Container 1 is still blocked at this point from an existing lock and change event.

Make the lock stale immediately and no extra sleep is required when paired with the helper method to wait until the event is processed (which should remove the stale lock).

- Simplify the test case so it's easier to grok.
- 2nd test case (blocking) extracts out initial setup into a separate method and merges the later service restart logic which is redundant.
- Additional comments for improved context of what is going on / expected.

- Add explicit counting arg to change detection support.
- Extract revised logic into it's own generic helper method.
- Utilize this for a separate method that monitors for a change event having started, but not waiting for completion.

This allows dropping the 40 sec of remaining `sleep` in `mail_changedetector` test. It was also required due to potentially missing the timing of a change event completing concurrently in a 2nd container that needed to be waited on and then checked.

- Switch to common container setup helpers
- Update container name and change usage to variables instead.
- Adopt the new convention of prefix variable for test cases (revised test case descriptions).

This has since been replaced with the new helper watches the `changedetector` service logs directly instead of only detecting a change has occurred via checksum comparison.

No tests use this method anymore, it was originally for `tests.bats`. Thus the tests in `test_helper.bats` are being dropped too. The new helper has test coverage in `changedetector` tests.

- A new lock should be created by this script after removal. The sleep doesn't help avoid a race condition with lock file creation after removal.
- Reduces test time as a bonus.
- Added some additional comments to test.

- No need to wait on the change detection service anymore during container startup.
- No need to count change events processed either as waiting a fixed duration is no longer relied on.
- This makes the reload count method redundant, dropped.

This test file was already adapted to the original common setup helpers.

- `TEST_NAME` replaced with `CONTAINER_NAME`.
- Prefix var added, test case descriptions drop explicit prefix.
- No other changes.

- New helper file for sharing these helpers to tests.
- Includes the helpful log method from changedetector tests.
- No longer need to maintain duplicate copies of these methods during the test migration. All tests that use them are now importing the separate helper file.
- `tls_letsencrypt.bats` has switched to using the log helper.
- Generic log count helper is removed from `test_helper/common.bash` as any test that needs it in future can adapt to `helper/common.bash`.

This helper does not seem useful as moving away from `supervisorctl tail` and no other tests had a need for it.

No other tests depend on this. Future tests will adopt the revised versions from `helper/setup.bash`.

Additionally updates `helper/setup.bash` comments that are no longer applicable to `TEST_TMP_CONFIG` and `CONTAINER_NAME`.

Review feedback

Co-authored-by: Georg Lauterbach <44545919+georglauterbach@users.noreply.github.com>

Review feedback request

Co-authored-by: Casper <casperklein@users.noreply.github.com>

This reverts commit ed8078b.