Added support for data-urls, text-scheme and inline SFCs

[terraloader]

Added support for data-urls:

• '/index.vue' is not appended to data-urls
• baseURI is empty to not include a base tag for data-urls

Added support for text-scheme:

• If URL start with "text:" the function does no XMLHttpRequest but uses the following text direct as SFC content
• If URL start with "#" its assumed that it is an element id of an inline script element that contains SFC content.

Data-URLs and Text-Method are really useful when you dont want to make extra web requests because you already have the complete content of a vue sfc.

I use this in combination with PHP to pre-include all needed components.
This is much more useful than only including a local "text/x-template" because a full vue component SFC can also have scripts and styles.

[Toilal]

@FranckFreiburger Do you plan to merge this pull request ?

[Toilal]

This could be used to implement a live component editor playground (code on left, rendered component on right).

[Toilal]

Well, now vue3-sfc-loader is there, maybe it makes much sense to make it support vue2 ...