Issue/1508-pagination

[cayb0rg]

Fixes #1508

• Adds pagination to the admin interface's instance search by piggybacking on the useInstanceList hook used in My Widgets Page
• Adds offset and limit to SQL query for instances in My Widgets Page
• Adds pagination to admin user search
  • This is also applied to the collaborator and extra attempts dialog
• Adds scrollbar to collaborator dialog user search results
• Set avatar sizes in user admin search to 50x50

[clpetersonucf]

Same as #1516, deleting the ucfopen/dev/10.0.1 force-closed this PR (sorry!). You'll have to remake it and target the new dev/10.1.0 branch instead. I would add a reference to this PR so the prior history and comments can be tracked.