[LiveComponent] Support loading states on an action-by-action basis

[FrancoisPog]

For now, the data-loading is added during all actions of the component (see docs), but it could be useful to know which action is triggering the loading.

Related to this message.

Thanks !

[weaverryan]

I'm working on this right now - the syntax will be data-loading="action(foo)|addClass(foo-loading)".

So, in this case, the foo-loading class will only be loaded if the foo action has been triggered :)