Refactor matching logic to use markdown AST

[A]

Problem

Current matchers are implemented as regexps and inlined into each entity class. Matching happens against the markdown content, and doesn't take AST into account. It creates a lot of edge cases and additional complexity to handle it.

Definitiion of Done

• matching of obsidian entities and markdown links happens on the AST level and creates AST-notes.

Links

• Mistune is a fast yet powerful Python Markdown parser with renderers and plugins.
• Mistletoe is a fast, extensible and spec-compliant Markdown parser in pure Python.
• Marko is a markdown parser with high extensibility.