DebugAdapter variables overhaul

[MichaelXt]

Fixes multiple issues with variables window for godot 4 projects.

Note: there is a great initiative of bringing DAP implementation directly into godot debug engine: https://github.com/godotengine/godot/blob/af56d6e8e88e56110577f3bbcfa2eb5cdcc71356/editor/debugger/debug_adapter/debug_adapter_protocol.cpp by @rsubtil and others. We will still need the backward-compatible implementation for now, which also includes remote scene inspector. In future, once the godot server DAP implementation matures, and where will be no need for backward compatibility, we should switch directly to it.

• Redesigned the representation of godot objects to match internal structure of godot server
• Lazy evaluation for the godot objects
• Stack frames now can be switched with variables updated

[DaelonSuzuka]

Thanks for linking that issue, I haven't been following engine development that closely so I didn't know this was happening.

Will the DAP implementation support the remote scene inspector?

[MichaelXt]

Should fix:

• Debugging: Node type variables show only ID Instead of details #729
• The debugger doesn't show any data #699
• Cannot view properties of an object extending Resource type during debugging. #660

Doesn't fix:

• All variables windows issues for godot 3.4. (Issues opened in 2022 and earlier)

[MichaelXt]

• Better presentation for arrays (in-line values, like in vscode javascript DAP)
• Callable and Signal vars are now displayed (though not expandable)

• Recursive Node references can be viewed properly:

[MichaelXt]

Thanks for linking that issue, I haven't been following engine development that closely so I didn't know this was happening.

Will the DAP implementation support the remote scene inspector?

I'm not sure - just found by looking at the code. @rsubtil should know better.

@DaelonSuzuka, could you review/recommend who can review this PR? Thanks again for maintaining and improving this extension, it is very useful!

[DaelonSuzuka]

Yeah I'm gonna review it tomorrow or this weekend.