Reacting to System.ObjectModel package version change
Adds missing ConfigureAwaits
fixing escaping aliases in sql queries - we used to not escape aliases for queries, so if user created query like: context.Users.Where(user => user.Id >5), we would create invalid sql. Fix is to start quoting those for all cases, so that any variables can be safely used. CR: Andrew
Only different in your mind... (Make ForeignKey and Index APIs consistent with Property and Key APIs)

This change removes the ForeignKeys and Indexes methods in the same way that Properties and Key were removed. The nested closure pattern on the Entity methods is now used consistently.