Removed dependency on $ from the highlighter

What does this MR do?

This is a unification of the syntax highlighter (used in GFM markup in particular) that allows the syntax highlighter to be used without jQuery. In particular, we now can:

• pass jQuery nodes (original behavior)
• a NodeList as a result of vanilla document.querySelectorAll()
• a Node as a result of vanilla document.querySelector()

Also, this allows us to have one more module jquery-free.

Screenshots or Screencasts (strongly suggested)

No visual changes:

Before (master)	After (this branch)

How to setup and validate locally (strongly suggested)

Does this MR meet the acceptance criteria?

Conformity

• I have included changelog trailers, or none are needed. (Does this MR need a changelog?)
• I have added/updated documentation, or it's not needed. (Is documentation required?)
• I have properly separated EE content from FOSS, or this MR is FOSS only. (Where should EE code go?)
• I have added information for database reviewers in the MR description, or it's not needed. (Does this MR have database related changes?)
• I have self-reviewed this MR per code review guidelines.
• This MR does not harm performance, or I have asked a reviewer to help assess the performance impact. (Merge request performance guidelines)
• I have followed the style guides.
• This change is backwards compatible across updates, or this does not apply.

Availability and Testing

• I have added/updated tests following the Testing Guide, or it's not needed. (Consider all test levels. See the Test Planning Process.)
• I have tested this MR in all supported browsers, or it's not needed.
• I have informed the Infrastructure department of a default or new setting change per definition of done, or it's not needed.