Model configuration: Set ValueGenerated for store-generated properties using a convention

[AndriySvyryd]

Currently setting DefaultValue, DefaultValueSql, ComputedColumnSql or SqlServer().ValueGenerationStrategy sets ValueGenerated in the Fluent API using ConfigurationSource.Convention.

This means that ValueGenerated is not updated when the mentioned facets are set using the Metadata API.

Also it might get out of date when merging the property facets since it doesn't use the same ConfigurationSource:
If DefaultValue is set by convention on base type, but ComputedColumnSql is set explicitly on base. When the base type is set the property will have ComputedColumnSql configured, but it could still have ValueGenerated set to OnAdd

[divega]

We should consider looking at other fluent APIs that do multiple things and can switch to using conventions. We should also evaluate if the complexity increase is worth the functional improvement we expect (in this case, mainly it is that setting the value in metadata APIs will have the same observable effect as doing it on the fluent API).

[JackLama]

More learning, mutual guidance