This is a refactor of the codebase to use a more memory-efficient
representation of notes. It should also be much faster at decoding since
we're using a custom C json parser now.
Changelog-Changed: Improved memory usage and performance when processing events
Switch the post parser to use the same code as the content parser. This
was causing many issues, including performance issues.
Changelog-Fixed: Fix lag when creating large posts
Changelog-Fixed: Fix npub mentions failing to parse in some cases
Changelog-Added: Add r tag when mentioning a url
Changelog-Removed: Remove old @ and & hex key mentions
