NEW ElementControllers extension point.

[mfendeksilverstripe]

ElementControllers extension point.

Description

Add an extension point for more flexibility.

Related Issues

• ElementControllers extension point #1321

Pull request checklist

• The target branch is correct
  • See picking the right version
• All commits are relevant to the purpose of the PR (e.g. no debug statements, unrelated refactoring, or arbitrary linting)
  • Small amounts of additional linting are usually okay, but if it makes it hard to concentrate on the relevant changes, ask for the unrelated changes to be reverted, and submitted as a separate PR.
• The commit messages follow our commit message guidelines
• The PR follows our contribution guidelines
• Code changes follow our coding conventions
• This change is covered with tests (or tests aren't necessary for this change)
• Any relevant User Help/Developer documentation is updated; for impactful changes, information is added to the changelog for the intended release
• CI is green

[GuySartorelli]

There's ongoing discussion about this change in the linked issue - but please note that the beta for CMS 5.4 has been released (we're just in the process of finalising it) so this change will need to target the 6.0 branch.

[mfendeksilverstripe]

Rebased now @GuySartorelli

[GuySartorelli]

Looks like you changed the base branch after pushing, so CI still thinks it should be testing against 5 even though the code is for 6. Can you please force push again so CI can run against the correct branch?

[mfendeksilverstripe]

Done @GuySartorelli

[GuySartorelli]

LGTM