some way for maps to opt out of multi-wave calling via /vnw

[DX-36]

for maps that need to activate certain events via wproc in scenarios such as:

• on an exact wave number
• every time a wave is called

and calling multiple waves simultaneously could break the wproc by causing it to trigger its event less times than expected compared to each wave being called one at a time
this could be done by using checking for a certain vanilla gamerule that has no effect on clients, I don't which one to use (maybe the map opts out if Wave Sending is disabled?)

[BalaM314]

We can probably use the locale bundles in v8