This expands the current dialogue tools runtime with a set of Actions, conditions and expressions to enable setting actors and opening the door to implement a story based game with much less repetition for changing of avatars, text color, actor stats and so on

Todo:

• Implement a new demo project to demonstrate how these features are to be used
  Demo here: https://github.com/blurymind/Gdevelop-dialoguetools-actor-system-demo
  

I can confirm that this does not change of the existing functionality unless you set up an actor that is detected in a dialogue line in yarn.

I have also made some minor changes to simplify some of the existing code a bit

Assiciated ticket that this closes #6461 and #6420 since the actor stuff relies on it

New features that greatly simplify setting up complex dialogue:

• Ability to create dialog actors and detect when they are the currently talking actor in yarn text lines

//in yarn
I am a normal line and I will work just the same as before
s: Hello, how are you? I am an actor line. If an actor with the id of "s" has been created, I will be treated differently
m: I am another actor line. The beginning "m:" will be stripped out of the text and DialogueTools will detect when I'm active
s smile: that is true! You can also pass arguments such as "smile" and dialog tools will tell the game when I am talking.
m: This makes it super easy to  dynamically change text color, avatars and so on when the active actor changes
s: what is useful is that the actor state is saved in yarn's state, that makes game saves and dynamic changes supper easy
// to change an actor's info, the pattern is as follows $a.[id].[variable]=newValue. Creating an actor simply sets those up
// this lets you easily change them during dialog or via the event sheet. A simple command is added to make this easier
<<set $a.s.color="123;12;123">>
// you can even attach your own values to an actor and use them to drive gdevelop events that update the avatars for example
<<set $a.s.face="smile">>

• Ability to easily set up an actor's name, emotes, color, and any other parameters and dynamically change those
• ability to get command parameter values via key like so (demonstrated use in the demo)
  <<command oldParameter keyedParameter=123 anotherKeyedParameter=true>>
• ability to get tag values via key like so (demonstrated use in the demo)
  tag anotherTag keyedTag:123 anotherKeyedTag:true
• basic ability to "fake" object variables in yarn, check if their keys exist, how many keys so we can iterate, delete object variables and so on. This is necessary for more complex games such as visual novels where we want to have better ability for yarn text to drive UI. The actor system is built on top of it