Support configuration of built-in supervisor and application

[christhekeele]

Expand the supervision story by adding a Mnemonix.Supervisor started in Mnemonix.Application

Interacting with it would work something like Ecto:

# In your config/config.exs file
config :my_app, :mnemonix, stores: [Sample.Store]

config :my_app, Sample.Store,
  adapter: Mnemonix.Redis.Store,
  options: [
    port: 9876,
  ]

Then when Mnemonix starts up it'd bring up those stores with it.

Considerations:

• deliniating between opts meant for the adapter and opts meant for GenServer
• how this would interact with Support creation of custom store modules #10
  • probably similar to Ecto a la use Mnemonix.Interface, otp_app: MyApp

[christhekeele]

Closed in v0.6.0.