CLN: remove duplicate banklist.html file
Wasn't quite a duplicate — had a missing `<tr>`. Also updated the `.gitignore` to more accurately only exclude HTML files from `doc/source/_static/`, since other files are checked in.

- [ ] ~~closes #xxxx~~
- [ ] tests added / passed
- [ ] ~~passes `black pandas`~~
- [ ] ~~passes `git diff upstream/master -u -- "*.py" | flake8 --diff`~~
- [ ] ~~whatsnew entry~~
