[WIP] Add SQLite database

[mpretty-cyro]

TODOs

• Add SQLCipher dependency
• Setup database connection logic
• Configure database to support the different platforms
• Enable WAL mode?
• Setup conventions for database migrations
• Setup interface for querying database
• Create table for config dumps
• Setup instance which takes a database path and key for database usage
• Update the config handling to use the database if ENABLE_DATABASE is ON
• Add a mechanism for clients to load existing config dumps into the database (ie. ones stored in their native clients)

Potential TODOs

• Add "observation" mechanism (underlying logic to support being notified of changes to specific tables/columns)

[jagerman]

Superceded by #103 (PFS branch).