Migrate to sql backed database

[olorin99]

Migrate from using a nosql database to an sql database. Using the drift package

Stores to migrate

• Accounts
• Feeds
• Feed cache
• Filter lists
• Profiles
• Server info
• Read post cache
• Misc
• Drafts

Other functionallity

• Add function on init to check for existing nosql db then migrate to new db.
• Add debug settings e.g. https://pub.dev/packages/drift_db_viewer

[olorin99]

I still need to do more thorough testing and make sure all weird database states migrate across properly but otherwise this should be ready for review.

With migrating from the old database to the new one I skip over migrating the feedCache since I got some weird errors when trying and figured that since it would just be recreated automatically when a user opens a feed it wasn't necessary. Every other sembast store should be migrated over though.

[jwr1]

I didn't see any other issues. After it's merged, I'll probably install a dev version on my phone just to see if I notice anything through daily use, since this is a pretty big change.

[jwr1]

Thanks for working on this migration, it looks great!