docs: Update io.cozy.bank.*

[Crash--]

Few doctypes were missing:

• io.cozy.bank.groups
• io.cozy.bank.recipients

I tried to document them, don't hesitate to complete

Thanks for contributing to this documentation. If you added a doctype, please be sure that it is present

• [x] in the Readme.md index page
• [x] in the toc.yml page