[Meta] stable release for localgov_microsites 4.0.0

[finnlewis]

@stephen-cox mentioned it would be good to have a pathway towards a stable release for localgov_microsites

@ekes mentioned that a few of the group ecosystem modules we use are using are still on the dev branches.

We can list out all the dev and non stable modules here are make a call as to which we need for a stable release.

[finnlewis]

We have a fair few live sites now:
Including:

• https://www.croydonlcsb.org.uk/
• https://www.haringeyfeast.com/
• https://jobs.oxfordshire.gov.uk/
• https://investwalthamforest.com/

Ekes: mentioned that we probably want a stable release of https://www.drupal.org/project/domain_group too.

[finnlewis]

I think we're nearly there.

We'll want to review and merge the following:

• Replace domain group resolver with localgov_microsites_group_get_by_c… #425
• Rationalise tests to use group ids 1, 2, 3, 4, 5 and add test for admin access localgov_microsites_group#459
• Add and enable antibot for some default spam protection out of the box. localgov_microsites_group#461
• ci: fix phpstan localgov_microsites_project#36
• Set environment variable SYMFONY_DEPRECATIONS_HELPER for phpunit localgov_microsites_project#45
• Set PHP version to 8.2 in default ddev config. localgov_microsites_project#46
• Require webform libraries with composer-merge-plugin. localgov_microsites_project#48
• Set if particular content types can be created in different Microsites localgov_microsites_group#428
• Add phpunit tests to cover enabling and disabling content types for a given microsite. localgov_microsites_group#464

Then hopefully all our tests will be passing and we can review for a beta or stable release.