Allow users to create and share saved dataset collections

[ahamelers]

Users should be able to save datasets to a profile collection.

• Allow users to create collections associated with their user account
• Add an option to chose or create a collection and save a dataset to it to the landing page
• Add an option to chose or create a collection and save a dataset to it to the search results page
• Limit 10 collections per user, 50 datasets per collection
• Provide a sharing link for the user to share their collection with others