Rethink about settings artifacts and exported_artifacts

[Lecrapouille]

Since 0.10.0, in godot script $CEF.initialize({ "artifacts": "xxx" ...,

• artifacts folder is already set by godot extension file.
• Therefore exported_artifacts and artifacts cannot be changed since libgdcef.so is loaded before godot script which is set where to find .so file.
• As consequence these are useless while we may want to change cef folder path.
• artifacts and exported_artifacts can be local/absolute path.

[pimhakkert]

We also need to catalog which files are actually needed for an export and which aren't. I'm sure there is a certain % of files that an export build doesn't need for CEF to work.