Instance filtering options

[clpetersonucf]

It'd be nice to finally include some instance filtration options on the My Widgets page. These might include:

• Draft/published widgets
• Has scores
• Score count over a certain value? (> 50, > 100 total scores recorded, etc)
• Shared with other users (this would require significant tweaks related to how instance perms are requested)
• Guest/Normal mode scoring

In several cases, this information is provided by additional API endpoints. We might have to reconsider what information is provided by instance get methods and how we could efficiently provide some of that additional information without significant strain on the DB (session caching, etc).

[chrissolanilla]

assigning myself this issue