Fix GitLab pipelines (tests, phpstan, phpcs, cspell) and reduce waste

Problem/Motivation

GitLab CI pipelines are currently failing. This includes not just linting jobs (phpcs, cspell, etc), but also phpstan (which can help us catch bugs) and most concerning, the automated tests themselves. We shouldn't be committing anything else to this project until we're sure we're not introducing regressions.

We've opt'ed in to a number of core version combinations, and currently all of those run on every push to every MR. This is generally wasteful of CI cycles. Instead, we can configure those to run manually, so they're trivial to trigger if you're looking at a pipeline, but they don't have to run all the time. The idea is that as an issue is getting close to RTBC / merge-able, we can trigger the full suite of compatibility checks to make sure we're not breaking anything in any of our supported versions.

Speaking of efficiency, we have a lot of tests, including long-running FunctionalJavaScript tests. We can both speed up our pipelines and save total CI time (which is what we're actually paying for), by setting _PHPUNIT_CONCURRENT: 1 to use run-tests.sh to run the test suite in parallel.

Finally, on the 2.0.x branch, we currently support D9 || D10 || D11, but we're only running tests on D10 + D11. So we can add some more core/PHP combinations (all requiring manual trigger) so that it's easy to make sure we're compatible and tests pass everywhere we say we are.

Steps to reproduce

Look at https://git.drupalcode.org/project/address/-/pipelines 😬

Proposed resolution

1. Get all the automated tests passing in all branches for all versions of core we support.
2. Define _PHPUNIT_CONCURRENT: 1 everywhere to run our test suite in parallel.
3. Fix all the linting / validation jobs (cspell, phpcs, etc).
4. On the 2.0.x branch, although we support D11, since we still support all versions of D10 (and D9), it's cumbersome to "chase HEAD" and resolve every new D11 deprecation. We're not going to be porting that to D12, so it's pointless. Therefore, add a phpstan-baseline-d11.neon file so we can easily put D11-only deprecations there without having to mess with the code.
5. Let the default 'composer' build run automatically, move all the other core/php combinations to manual triggers.

Remaining tasks

User interface changes

API changes

Data model changes

Original report by @anybody

Fix code style (phpcs. phpstan, styleint, cspell, eslint, ...), see pipeline warnings