Switch to the new code parser version
This MR replaces the old code parser with the new version introduced in !260 (merged).
The new version provides exactly the same functionality:
- extracting imports
- counting three-sitter symbols
Differences:
- The DFS algorithm to traverse the tree
- Ruby support
- Counted symbols are pure "threesitter" names, not mapped to abstract terms like
class,import,method, etc.
Closes #232 (closed)