Add repeat action & tweak untrigger filter

[Pablete1234]

Modifies the 1.5 proto default behavior for untrigger-filter back to never whenever the action is filtered. This is because we've realized that otherwise recursive actions will cause infinite recursion on untrigger by default, which is undesired behavior.
So now in proto 1.5, when an action has no filter, it defaults to untrigger-filter="always", but whenever it's filtered or map is in an older proto, it defaults to never.

Additionally a repeat action has been introduced. This allows for loops without recursion within actions:

<actions>
  <repeat times="var * 2" filter="allow">
    <message text="This message is repeating a bunch of times!"/>
  </repeat>
</actions>

When var is 5, this will send the message 10 times in chat. Note that times takes in a function, so you can do things as simple as times="5" or as complex as to mix-in variables, and math operations. Non-whole numbers will be rounded down, negative numbers will cause no iterations (it won't run the inner action).

The filter will be run as many times as the loop is ran, for performance reasons if you want the filter to be checked just once move it outside the repeat like action filter="x" -> repeat.
Untriggering has no effect whatsoever over the repeat action, it will not propagate any untrigger signal downwards