[CLEANUP] Remove deprecated jQuery integration

[simonihmig]

This removes the Ember.$() and this.$() jQuery integration, deprecated by RFC386.

There is still more work to do, but I wanted to keep the scope of PRs small:

• remove EventDispatcher jQuery code - hopefully we can get Enable global event dispatcher listeners to be lazily created. #19227 merged first to not again cause major merge conflicts. @rwjblue 😬
• further internal cleanup

Note: as a breaking change, this should only get merged when it's clear that current master represents the "4.0 train" - not 100% sure if that decision has been taken already!?

[rwjblue]

will likely need a rebase?

[simonihmig]

will likely need a rebase?

I had to fix a linting error, but other than that this should be ok!

[rwjblue]

Due to some complications with 3.27's migration to use real modules (and the resulting massive number of deprecations being triggered) we are not 100% certain (yet) that 4.0 will be the version just after v3.28.

In order to move ahead with v4.0 cleanup efforts (like this one), I've pushed a new branch that can serve as the target for breaking change PR's: https://github.com/emberjs/ember.js/tree/v4-cleanup.

I've updated this PR to target that branch, can you rebase against that branch and push an update?

Expand for an example of the commands needed for that rebase.

# starting from this PR's branch

git fetch origin
git rebase origin/v4-cleanup

# fix any conflicts

# push the rebase
git push -f

Those steps should be roughly what you need, but might need some tweaks based on your local repository setup (e.g. if you don't use origin for the main emberjs/ember.js repo you might have to use another remote name there).

Thank you for helping us push things forward!

[simonihmig]

Done

[mixonic]

I'm not clear on where we sit with the v4-cleanup stuff now. master is currently 4.0, so I would land this if it was pointed there.

[mixonic]

@simonihmig this PR was auto-closed when v4-cleanup was merged to master. Can you re-open for us to review/merge against master? This is excellent work and I don't want to lose it.