Boot time database init to deprecate nv migrate

[christiansmith]

There are a handful of values that must exist in the database in order for the server to work as expected. These include the openid, profile, and realm scopes and the authority role, along with default permissions.

At present, these values are created by running nv migrate before first running the server. This is not ideal for a variety of reasons. First, if overlooked, auth flows won't work correctly. Second, it's a pain to run this in the context of a Docker based deployment.

I propose that as part of the bootstrapping process, the server should check the database for the existence of these values and create them if they're missing. This also gives us a convenient place in the code the throw an error if the database is unreachable, resolving #39.

[christiansmith]

A draft of this behavior (sans unreachable Redis error) now lives in the bootdb branch: 904d744

[adalinesimonian]

Merged #142