Add Comment section to Applicant profile, create some action to handle the creation and get the notes by profile

Style

Homework page

Fixed the issue with no File but with description. Now you will see the description with solutions sent with no file. The admins will see the full names at the solution details panel instead of the nicknames too.

You can now send solution without a file, the admin will see a 'No file' tag.

This is due to the demand of non-bordered task links.
Also added some styling for hover.