Introduce persistent application state

[srid]

Use a sqlite db dioxus persistance to store application state which includes:

• Recent flakes accessed Persist Signal state to disk (recently visited flakes now persist) #98
• Flake output structure Cache retrieved flakes on disk #101
  • Once we "cache" the outputs in the DB, it can be shown without having re-evaluate the flake again. This can be useful for large projects with IFD, like nammayatri, or even nixpkgs. The UI will open ready to do search for packages, etc.
• UI indicator for stale data. If a flake is out of date, encourage user to update it. Then update the SystemTime in the cache.
• User settings if any (in the future)

[srid]

Let's consider DioxusLabs/sdk#17 over sqlite ...

[srid]

This is now done, opened #102 for the last task.