Add support for the Godot Language Server

[Jummit]

By default Godot 3 uses port 6008, but this will be changed to 6005 in Godot 4.

Launch command copied from https://github.com/neovim/nvim-lspconfig/blob/master/lua/lspconfig/server_configurations/gdscript.lua

Users who use Godot 4 right now need to change the port in the editor settings.

This also changes the indent to tabs, based on the official style guide.

[coelhucas]

Is there anything else for this to be merged rather the conflicts, @Jummit @archseer?

[kurushimee]

Yeah, this still works and is still needed.