Allow user ability to curate knowledge elements on platform

[beckvalle]

Is your feature request related to a problem? Please describe.
As the number of knowledge elements contributed grows, a user will have trouble keeping track of the ones they are interested in. This is especially important for non Notebook elements.

Describe the solution you'd like
The I-GUIDE platform should allow a user to save and organize knowledge elements that they are interested in for easy access when they return to the platform.

Some potential aspects:

• User "saves" or "bookmarks" or "stars" a knowledge element of interest.
• These saved elements should be viewable from a separate page (just showing saved elements).
• Users should be able to add private tags and notes to saved elements (only viewable to that user).
• The user should have an option to limit element searches on the platform to only saved elements.
• Users should be able to save both their own contributed elements and elements contributed by other people.
• If tags and notes are implemented, user should be able to view saved elements by tag and search within personal notes.