Implement SSR 12y2 parser?

[randomouscrap98]

I have been told reimplementing 12y is a bad move, so I'd like to implement a subset of the 12y2 spec. I've also been told converting the 12y pages into 12y2 will be easy, so... hopefully that's the case! So I'd like to:

• Make an SSR 12y2 parser which outputs the SAME html as the bbcode parser
• drop support for 12y
• convert 12y pages to 12y2
• Fix issues that arise (because they will arise)

Here's a test suite: https://12me21.github.io/markup2/testing/index.html