Use module specifier algorithm for URLs

[RoyalIcing]

• https://html.spec.whatwg.org/multipage/webappapis.html#resolve-a-module-specifier

1. Apply the URL parser to specifier. If the result is not failure, return the result.
2. If specifier does not start with the character U+002F SOLIDUS (/), the two-character sequence U+002E FULL STOP, U+002F SOLIDUS (./), or the three-character sequence U+002E FULL STOP, U+002E FULL STOP, U+002F SOLIDUS (../), return failure.

The following are valid module specifiers according to the above algorithm:

https://example.com/apples.js
http:example.com\pears.mjs (becomes http://example.com/pears.mjs as step 1 parses with no base URL)
//example.com/bananas
./strawberries.js.cgi
../lychees
/limes.jsx
data:text/javascript,export default 'grapes';
blob:https://whatwg.org/d0360e2f-caee-469f-9a2f-87d5b0456f6f

The following are valid module specifiers according to the above algorithm, but will invariably cause failures when they are fetched:

javascript:export default 'artichokes';
data:text/plain,export default 'kale';
about:legumes
wss://example.com/celery

The following are not valid module specifiers according to the above algorithm:

https://eggplant:b/c
pumpkins.js
.tomato
..zucchini.js
.\yam.es