Sprint: Added new external resources page, link from main and content pages
FIX See also in axes docstrings wasn't formatted properly

closes #2224
Merge pull request #2231 from NelleV/2224

FIX See also in axes docstrings wasn't formatted properly
Updated index page text and added another video
Merge pull request #2165 from alsaihn/new_resource_page

Sprint: Added new external resources page, link from main and content pages