feat: drupal 11 support

[millnut]

What does this change?

Fixes #280

How to test

localgovdrupal/localgov_services:"dev-feature/2.x/drupal-11-support as 2.1.15"

Failures are eslint and stylelint, not related to D11 support.

How can we measure success?

Module works with both D10 and D11

[ekes]

Usual 8.4 contrib issues.

But also test depends on workflows first.

1) Drupal\Tests\localgov_services\Functional\WorkflowsIntegrationTest::testPostLink
Unable to install modules: module 'localgov_workflows' is incompatible with this version of Drupal core.

/var/www/html/web/core/lib/Drupal/Core/Test/FunctionalTestSetupTrait.php:505
/var/www/html/web/core/tests/Drupal/Tests/BrowserTestBase.php:555
/var/www/html/web/core/tests/Drupal/Tests/BrowserTestBase.php:367
/var/www/html/web/modules/contrib/localgov_services/tests/src/Functional/WorkflowsIntegrationTest.php:57

OK looks like that's one got overlooked :-( localgovdrupal/localgov_workflows#114 almost there localgovdrupal/localgov_workflows#123

[finnlewis]

Logged this issue to fix PHP 8.4 issues: #299