Adding information to the model about whether the bool metadata properties have been set to default values explicitly.
Use me! Use me!

Update stack to use new provider-specific APIs

And remove older APIs. This updates query, Migrations, and update pipeline to use the new annotations through the new APIs and to use provider-specific annotations, rather than just relational annotations. File issues for:
* SQLite provider-specific APIs and their use
* Clustered is SQL Server specific except in Migrations
* Use of SQL Server specific values for column names in query
* Cascade deletes are not supported in the stack
Query: Relational: Enabled Include for async queries.

- Added async include tests to SQLServer, SQLite
- Fixed some async call sites that were not flowing a cancellation token.
- Some further de-nesting of query component classes.
Query: Relational: Async: Make All/Any/Count non-blocking.
Autumn Cleaning - Cleanup in Database Error Page

Removing isDevMode since this concept is handled in Startup.cs.
Keeping UseDatabaseErrorPage behavior consistent with general ASP.NET UseErrorPage:
* Parameterless overload results in everything being shown.
* Adding DatabaseErrorPageOptions.ShowAll pattern to allow UseDatabaseErrorPage(DatabaseErrorPageOptions.ShowAll)

Updating UseDatabaseErrorPage to also register the Migrations Endpoint when it's going to be needed