Add automated issue detection for admins

[danieliser]

Some issues we should try to detect where possible:

• [ ] If multiple copies of jQuery have been loaded on the page. Possible solutions include looping through all script[src*="jquery"] then parsing for common naming variations.
• [ ] If there are JS errors on the page: https://blog.sentry.io/2016/01/04/client-javascript-reporting-window-onerror
• [ ] If there are multiple forms with the same ID on the page.
• [ ] If there are popups with typically bad combinations of settings.
• [ ] If there are more than a few popups on the page it should recommend adding targeting conditions.

[fpcorso]

@danieliser Should we punt this one to 1.10?

[danieliser]

Punting for now.