Create Setup Classes to allow configuration without writing real HOCON

[to11mtm]

With other parts of Akka.Net having ActorSystemSetup and similar, it would be nice to have the same capabilities here so that users can easily set up plugin configurations without having to write a bunch of HOCON.

This class should allow for configuration of all the 'important bits' that are exposed in HOCON configs.

• It may be nice to provide a sort of 'forwarding' for providername with our own type/enum so users don't have to poke at Linq2Db.ProviderName
• Validation/warning on invalid configs would also be a good idea (fail fast)

[Aaronontheweb]

@to11mtm after some of the work we were doing on Akka.Persistence.Redis earlier this week, I was considering proposing this for Akka.Persistence in general - having a PersistenceSetup that can be subclassed and used to provide implementation-specific configuration.

The use case I really like this for - being able to pass in connection strings programmatically.

[Aaronontheweb]

Akka.Peristence.Sql.Hosting solves this issue.

[Aaronontheweb]

Eh, guess not - we need this for stuff like pass-through identity, akin to what we do for Akka.Persistence.SqlServer