Dashboard insight setup

[liyiy]

Changes

Round 2 of dashboard insight page setup 😄 for #3551

1. Set up separate component and logic files for this page. The route is accessible only if you manually go to /dashboard_insight/${id}

2. Moved over the dashboard item description editing stuff I had worked on

TODO for a separate, next PR

• Address the actual filters handling !
• Address the look and size of the graphs
• Address more detailed description/title editing
• Address somewhat duplicate code with the mapping like how the DashboardItem component renders its own charts
• Include a e2e test or two 😓

Overall Page View

Description editing
https://user-images.githubusercontent.com/25164963/117879267-c3735c80-b274-11eb-999f-c8fb2a42049a.mov

Checklist

• All querysets/queries filter by Organization, by Team, and by User
• Django backend tests
• Jest frontend tests
• Cypress end-to-end tests
• Migrations are safe to run at scale (e.g. PostHog Cloud) – present proof if not obvious

[paolodamico]

Hey @liyiy! With this PR it'll be important to consider the changes from #4314, as the new querying experience will require a different approach to the UI. Let me know if you want to sync on this.

[liyiy]

Hey @liyiy! With this PR it'll be important to consider the changes from #4314, as the new querying experience will require a different approach to the UI. Let me know if you want to sync on this.

Yes, let's sync on that.