Investigate augmenting model with EF code-first model metadata

[ascott18]

Problem

Many EF features can only be configured via OnModelCreating, which Coalesce cannot be aware of.

Solution

If we could figure out how to access this data at generation time (getting it at runtime is easy), that would open the doors to a whole new world of features. Investigate how this works in EF tooling like migrations or compiled models.

Also see dotnet/efcore#11659