[ENGINE] Create task to handle NPCs shouting regularly

[Jameskmonger]

• We should make some reusable task that can be used for NPCs which regularly shout (with some random intervals supported too)

This would be used in:

• Sheep saying "baa"
• Town criers
• [todo] add more

[Promises]

Think the most advanced example is the falador guard joke plugin

[Jameskmonger]

@Promises probably a bit too complex for the purposes of this ticket as it involves the multiple NPCs and the animations etc. I have made a ticket to track that (and others) as #417