Currently, you have to implement an empty class for any local task plugin. This is a bit weird, you are then just using the empty class for the annotation. It makes sense, similar to routes, to have YAML discovery for these, then static local tasks just get added into a $module.localtasks.yml file. This seems like better UX, as people can then actually create a plugin class for dynamic local tasks.
Annotations for local tasks go away.
Caching is removed and will be handled in a follow since the strategy is being developed in parallel. (related issue below)
PASSED: [[SimpleTest]]: [MySQL] 59,036 pass(es).
PASSED: [[SimpleTest]]: [MySQL] 58,553 pass(es).
PASSED: [[SimpleTest]]: [MySQL] 58,392 pass(es).