use Either type for UrlOrNone

fix test-tidy errors

fix style unit test

use the Parse trait instead of ParseWithContext

fix stylo test and geckolib build

move all specified url parse code to parse trait and remove refs to unused type

components/style/font_face.rs

@@ -8,7 +8,7 @@
 
 use computed_values::font_family::FontFamily;
 use cssparser::{AtRuleParser, DeclarationListParser, DeclarationParser, Parser};
-use parser::{ParserContext, log_css_error};
+use parser::{ParserContext, log_css_error, Parse};
 use properties::longhands::font_family::parse_one_family;
 use std::fmt;
 use std::iter;