Revert "Unify http- and percent- encode/decode"

[RandomShaper]

This reverts commit b76ee30.

The reverted commit is the one from #17583 that has caused some trouble.

[aaronfranke]

@RandomShaper @akien-mga Can the removal of the percent_ methods be re-evaluated for 4.0? I can't reproduce any issues with this, the only difference that I can see is that one uses uppercase letters and the other uses lowercase letters.

	print("Ж Godot Engine:'docs'".percent_encode())
	print("Ж Godot Engine:'docs'".http_escape())
	print("Ж Godot Engine:'docs'".percent_encode().percent_decode())
	print("Ж Godot Engine:'docs'".http_escape().http_unescape())
	var http = HTTPClient.new()
	var dic = { 'arg1' : 'Ж', 'arg2' : 'foo' }
	print(http.query_string_from_dict(dic))

Output:

%d0%96%20Godot%20Engine%f0%9f%99%82%3a%27docs%27
%D0%96%20Godot%20Engine%F0%9F%99%82%3A%27docs%27
Ж Godot Engine:'docs'
Ж Godot Engine:'docs'
arg1=%D0%96&arg2=foo

For #17583, it seems that the only reason these were kept is because of GDNative compatibility. If that was the concern, then a wrapper method should've been kept instead of keeping a duplicate method in core. However, we have the opportunity to break compatibility with GDNative for Godot 4.0.

[akien-mga]

This could be redone yes, or even back to the original implementation which unified those as uri_encode.

[aaronfranke]

Yeah. Also, I noticed this comment: https://github.com/godotengine/godot/blob/master/tests/test_string.h#L1166

[RandomShaper]

I'd take some inspiration from the JS URI encode API: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/encodeURI

Maybe we even would better have separate full and component-wise encoding methods. If I remember correctly, when I worked on that, I considered the possibility, but I can't remember the reason now.