feat: Added ability to print globals as part of debug messages

[balloonpopper]

This allows debug messages to print the contents of globals. Globals are indicated by brace symbols " { } "

debug "r3_button_broken is currently {r3_button_broken}"

I have added the function to resolve globals to all debug levels (info, warning etc) but due to bug 219 I can't test other debug levels so I'm not sure if the behavior is correct.

If everyone's happy with the "{ global }" notation, I'll need to update the documentation in the documentation repo.

The alternative is Godot string notation

debug "Name %s is %d years old", name, age

But I don't know how to extend the parser to cope with this so I went with what I knew how to code :D

Output for valid global

2022-4-3T11331 (D)	Running command debug with parameters [r3_button_broken is currently True] 	
2022-4-3T11331 (D)	debug command issued 	[r3_button_broken is currently {r3_button_broken}]

Invalid global :

2022-4-3T105254 (D)	Running command debug with parameters [r3_button_broken is currently Null] 	
2022-4-3T105254 (D)	debug command issued 	[r3_button_broken is currently {invalid_global}]

Fixes godot-escoria/escoria-issues#205

[StraToN]

Thanks!