Migrate cli.ConfigService calls to fully typed config.ConfiguService calls

[DavidS-ovm]

To reduce clutter, unify the server-side implementation, and provide better type safety the CLI config currently using GetConfig/SetConfig in cli.ConfigService needs to move to a pair of typed per-user functions in config.ConfigService.

• update sdp definitions
• implement new functions in api-server, using the old storage location as fallback
• update CLI to use new functions
• re-implement cli.ConfigService as legacy shim on top of the new API.