Add offline script verifying support using custom build of Godot

[Razoric480]

• This refactors the code to split the ScriptVerifier class to make it into a base class, with test() as a virtual function to override, and implements a OfflineScriptVerifier class. Common functions and data have been moved into the ScriptVerifier.

  • LSP based verification has been removed.

• The OfflineScriptVerifier class depends on the GDScriptParserWrap Reference class, which is not part of Godot by normal. It requires a custom build of Godot. I've uploaded export templates that include this class at https://github.com/Razoric480/godot/releases/tag/3.4.4-parser, which are compiled on my fork https://github.com/Razoric480/godot/tree/raz/gdparser-expose. Including them as a binary data through a git push is a bad idea given the size. I'm unsure of a better way - would be some CI magic of sorts I imagine.

The GDScriptParserWrap class exposes the parse(script_content: String), has_error(), get_error(), get_error_line() and get_error_column() functions by wrapping Godot's GDScriptParser class, which isn't normally visible through scripting. I didn't expose warnings because they are only visible during tools (though we blacklist anything of that severity anyway.)

• global/... settings removed.
• References to the LSP mostly removed, files and classes renamed in consequence, like LanguageServerError just being ScriptError and LanguageServerRange becoming ErrorRange.
• References and UI related to connecting to a server removed.

Close #300
Fix #310

[NathanLovato]

Thanks for your work @Razoric480, this is a massive improvement.

May I ask you to remove the option to switch entirely, and rather remove the LSP part? It'll still be in the code history should we ever need it (we could keep it in a branch), but the idea's to get rid of it entirely. I can help with removing UI bits like the server connection indicator.

[Razoric480]

@NathanLovato Done - I've excised 99-ish% of LSP-ness from the project. Preliminary test reveals it's still working, though users have a knack for finding issues so we'll have to see if I messed something up.

[NathanLovato]

Thank you very much François, great work you did there, as usual :)

I'm a bit busy preparing the course release but will test and merge as soon as I'm through with my todo.

[NathanLovato]

After testing, it's working like a charm. I'll address some bugs in the app today, make a stable release, then we can merge this and update the CI for the following release.