Allow users to add to the favorites section of a folder view

[triptych]

To be able to

1. drag a folder or file to the favorites view
2. rearrange or delete files and folders from the favorites view
3. right click on a folder or file and see "add to favorites" as a menu option

[jelveh]

Needed for sure.

[kristavlastou]

Hello, can you assign me and @EvaNtziou to this; We are new to the project and we are looking forward in cooperating for this issue

[KernelDeimos]

partly assigned. @EvaNtziou please comment here and I'll assign you too, GitHub makes this difficult

[EvaNtziou]

Hello, thank you for assigning us