Fixes for running ci against main Moodle branch

[danowar2k]

I forked the plugin to check for the combination of PHP 8.1 and Moodle 4.1 compatibility. I had to fix a few things while doing this:

• Moodle's master branch was renamed to main
• The main branch needs Postgres 14 instead of 13
• You use moodleou/qtype_recordrtc in your Behat tests, so I added it and its dependencies to the install

I also changed:

• IMHO phpcs should always only test up to the PHP version that's used

Anyway, one Behat test is still failing (https://github.com/danowar2k/moodle-filter_embedquestion/actions/runs/12836059633/job/35796878521#step:17:173).

001 Scenario: Test display of Save button for embedded recordrtc question. # /home/runner/work/moodle-filter_embedquestion/moodle-filter_embedquestion/moodle/filter/embedquestion/tests/behat/filter_embedquestion.feature:114
      And I should see "Save"                                              # /home/runner/work/moodle-filter_embedquestion/moodle-filter_embedquestion/moodle/filter/embedquestion/tests/behat/filter_embedquestion.feature:125
        "Save" text was not found in the page

If I knew the plugins in question I'd probably be able to see what's happening there. Or if I'd have screenshots, but at the moment I don't have local Behat/Selenium/etc. set up.

Anyway, maybe the fixes help....