Fix API consistency errors in metadata

[AndriySvyryd]

Add more Metadatada API consistency tests
Refactor ApiConsistencyTest

Consistency errors fixed:

• All mutating methods should have a bool fromDataAnnotation = false parameter on IConvention*
• All mutable facets should have a corresponding Get*ConfigurationSource() method on IConvention*
• All mutable facets should have a corresponding CanSet*() method on IConvention*Builder
• Fluent API can only be prefixed by "Has", "HasNo", "To", "Is". Metadata API can only be prefixed by "Add", "Remove", "Get", "Is"
• Provider-specific extensions should have matching IModel and IMutable* methods
• Set* methods on IMutable* types should return void and on IConvention* should return the configured value
• Remove* methods on IMutable* and IConvention* type should return the removed value

Fixes #17360
Fixes #20269

[ajcvickers]

@AndriySvyryd So...how breaking is applying these rules now?

[AndriySvyryd]

@ajcvickers Since there's still no public API for adding conventions the impact on the vast majority of users should be minimal. We'll discuss each actual change in the API review.