Rather than using two properties to enable or disable reactive and
imperative repositories for a particular store, this commit introduces
a new repository type condition that's backed by a single
spring.data.<store>.repositories.type property. The type can be
auto (automatically enables whatever's available), imperative (enables
imperative repositories), none (enables nothing), or reactive (enables
reactive repositories). The default is auto.

Repositories do not have a reactive option (such as JPA) continue to
have a spring.data.<store>.repositories.enabled property that takes a
boolean value.

Closes gh-11134