DOC: move info docs to DataFrameInfo
- [ ] closes #xxxx
- [ ] tests added / passed
- [ ] passes `black pandas`
- [ ] passes `git diff upstream/master -u -- "*.py" | flake8 --diff`
- [ ] whatsnew entry

Precursor for #37320
Move ``info`` docstring from ``pandas/core/frame.py`` to class ``DataFrameInfo`` using ``doc`` decorator.

@simonjayhawkins need your help here as discussed previously.