Use gd_user everywhere for better performance

[vlad-timotei]

To provide customized experiences (and to prevent errors) we check in the entire project some tings several times in various more or less performant ways.

Since #320, thanks to @webaxones we have a new object that stores all the information needed, obtained using performant methods.

GlotDict/js/glotdict.js

Lines 20 to 25 in f6973ff

	const gd_user = {
	is_translator: false,
	is_editor: false,
	is_connected: false,
	is_on_translations: false,
	};

But we don't use it yet. There are a few chronological things to do:

• 1. Move gd_user generation code from glotdict.js to glotdict-user.js and load glotdict-user.js first. We want to keep the loading of everything else in glotdict.js last, as proposed by @Mte90 here. We could also move it to another file that loads first, such as glotdict-settings.js, if we don't want an additional file.
• 2. Find all the checks that can safely be replaced with gd_user evaluations.
• 3. Replace all of the above.

This would uniformize the checks and improve performance.