Medical - Add treatment status events

[ghost]

Adds

• ace_medical_treatment_treatmentStartedLocal
• ace_medical_treatment_treatmentSucceededLocal, and
• ace_medical_treatment_treatmentFailedLocal
  CBA events. All of them have the same six parameters passed unchanged from the treatment action:
  _medic, _patient, _bodyPart, _classname, _itemUser, _usedItem.

Rationale:
I've been trying to write a ShackTac-style medical extension without forking ACE. When trying to add a "PlayerName is bandaging you"/"You are being assisted" hint, I've been stopped by the following drawbacks in existing ace_medical_treatment_{TREATMENT}Local (e.g. ace_medical_treatment_bandageLocal) events:

1. They are not a single convenient entry point;
2. They do not carry a _medic parameter.

Here's an example of someone else trying to do this kind of hint with the existing API. I think this PR would improve the situation.

Existing "ace_treatmentSucceded" event seems grandfathered in from before the medical rewrite, so I'm leaving it alone.

[BrettMayson]

These don't need to have Local at the end of them, that is implied by localEvent and is documented.

It looks like these should also be simplified to ace_treatmentStarted rather than ace_medical_treatment_treatmentStartedLocal, but I'd let someone else confirm that

[ghost]

Removed the Local tags.

Quite a lot of events in ACE are QGVAR. Is this convention supposed to be internal then? If yes, I could append the arguments to ace_treatmentSucceded instead of making a new event.

[ghost]

• Updated ace_treatmentSucceded with _itemUser and _usedItem parameters;
• Renamed other two events to ace_treatmentStarted and ace_treatmentFailed

[kymckay]

Yes I believe we decided at some point that QGVAR events for internal only and public events can just use ace_, probably not documented anywhere though

[PabstMirror]

lgtm