Cvldoc-parser

Added
- Support parsing of `hook`, `use`, `using`, `import` statements.
- Python module API has been simplified.
- Support `persistent ghost`.
Changed
- CVL2 syntax is now enforced. Parsing of code which is not compliant with CVL2 has been removed.
Fixed
- Some issues with `Invariant` parsing have been fixed.

Fixed
- Fix issue that could cause infinite recursion on certain input
Changed
- Upgrade dependencies
- Merged Python wrapper and core changelogs to a single file

Fixed
- Use span-based capturing for `Definition`

- Release Candidate for first public version

Fixed
- Correctly report span for raw code of starred documentation blocks
- Incorrect detection of code blocks
- Handle variable-length characters
- Python wrapper: Comptability with parse API change

Changed
- Parsing engine re-written
Changed
- Data structure of AST changed, first class member is now `CvlElement`
- Can now handle elements without documentation
- Python wrapper: Breaking changes to data structure API
Fixed
- Fix detection of invariants and other elements
- Improve parser recovery and robustness
Removed
- `serde` support removed for now