Add API to configure construction of entity type instances

[ajcvickers]

Issue #10703 covered the ability of EF to call a parameterized constructor. However, the constructor to use is not configurable. This issue is about adding fluent API and/or annotations to do this and also:

• How properties are bound
• Injecting services or service methods--i.e. generalized case of ILazyLoader and its related delegate
• Configuring a factory method instead of using a constructor directly
• Consider NotMapped/Ignore to just exclude a constructor from being used by EF

[todd-skelton]

Is there any workaround to prevent parameterized constructors from being used until it's configurable? I have creation events in my constructors and they are getting raised every time the objects are queried.

[ajcvickers]

@xKloc Starting with preview2, if there are both parameterized and empty constructors, then EF will choose the empty one. See #10852