Access DB with a generic Provider

[liamaharon]

The ProviderFactory type rbuilder uses internally for DB ops is deliberately not exposed by the reth node to services running in-process alongside it, making it impossible to access and forward the node's ProviderFactory to the rbuilder when creating it in-process.

To resolve this, usage of the concrete ProviderFactory can be replaced with a generic Provider trait bounded by whatever it needs from here. This should allow rbuilder core to support
the provider exposed by reth when run in-process, and also a ProviderFactory created when the DB connection is opened independent to the node out-of-process.

Note that as well as allowing rbuilder to run in-process, this is also a necessary step to support the new reth engine (default now in reth v1.1) which does not use the ProviderFactory.