[6.0] Updating dependencies

[Hackwar]

Summary of Changes

This PR updates the Joomla framework to v4 and also updates all related dependencies to the latest major version necessary. This PR depends on the following PRs to pass:

• [6.0] update JOOMLA_MINIMUM_PHP #45746 (Set the new minimum PHP version to 8.3)
• [5.4] HTTP: Remove legacy code for Response calls #45825 (Remove legacy calls to Response class)
• [5.4] Converting DatabaseQuery::castAsChar() to castAs() #45826 (Convert DatabaseQuery::castAsChar() to castAs())
• [6.0] Replace all joomla/string inflector code #45040 (Remove calls to String/Inflector)

Only after these are merged, this PR can be updated and should then pass. Testing before then unfortunately is not really going to help.

Testing Instructions

Codereview

Link to documentations

Please select:

• Documentation link for docs.joomla.org:

• No documentation changes for docs.joomla.org needed

• Pull Request link for manual.joomla.org:

• No documentation changes for manual.joomla.org needed

[richard67]

@Hackwar Now 3 of the required PRs have been merged, and I've updated the branch of this PR to the base branch and fixed the conflict. The only show stopper now is PR #45040 . It could be hard to find testers by code review. Do you have an idea for some testing instructions for that PR so we come forward?

[Hackwar]

Now that all depending PRs are merged, this PR is also ready and could be tested/merged.

[richard67]

As the testing instructions are "Code review", I did so and can say it looks all right.

Should we try to get some human tests in addition, e.g. for building packages or something like "check if everything still works"?

[wilsonge]

We need the dependency updates before the feature freeze this weekend. So I'm merging this ahead of that, understanding there's no tests but hoping the system tests give us a good enough baseline.