Move desktop and server backend to SQLite

[eatonphil]

This PR rewrites the way data is stored:

• Before this PR, all data was managed by the UI. The entire project state was passed back on every change
• Panel result storage was managed by the UI too, and some other things like incrementing lastVersion of the project and so on, lastedited on a panel, etc.
• This PR switches from a single JSON blob to slightly normalized tables for panels, pages, servers, connectors, and panel results
  • Within each table however there is still mostly just a JSON blob
• This allows the UI to send smaller requests for only the exact object that needs to be modified
• And now the runner is in charge of writing panel result updates back to the database, rather than the UI
• Integration tests are currently in place for the backend changes
• Automatically migrates JSON projects to SQLite

This is now basically working on new projects: desktop, server, and in-memory browser.

This PR drops (for now):

• Dashboards and export. It's taking too long and these need an overhaul