This commit removes the old parser, the deprecated parser module, the old parser compatibility flags and environment variables and all associated support code and documentation.
This commit makes both APIs more consistent by doing the following:
- Remove the `PyPegen_CodeObjectFrom*` functions, which weren't used
and will probably not be needed. Functions like `Py_CompileStringObject`
can be used instead.
- Include a `const char *filename` parameter in `PyPegen_ASTFromString`.
- Rename `PyPegen_ASTFromFile` to `PyPegen_ASTFromFilename`, because
its signature is not the same with `PyParser_ASTFromFile`.
This commit also allows to pass flags to the new parser in all interfaces and fixes a bug in the parser generator that was causing to inline rules with actions, making them disappear.
