[Epic] Remove old jQuery-based functionality from the code base

[kimadactyl]

Description

All of our jQuery depends are showing their age and don't play nicely with our test suite, requiring multiple workarounds and so forth. Putting more energy into maintaining them seems a bit of a dead end compared to just migrating them to a more modern alternative using Stimulus or similar.

To remove it all we need to:

• Remove datatables (Improve datatables #1137)
• Rewrite the event browser ([Bug]: Event browser behaving erratically #2565)
• Remove Select2 and replace with something more modern, probably Tom Select
• Remove jQuery gems and depends from codebase
• Store javascript and css with components #2562
• (add more if we find them)

Motivation

Javascript should be in one paradigm and used in one way in the code to make it easier for other people to contribute and not have clashing paradigms in different places.