.Net: Memory Connector documentation

[markwallace-microsoft]

Create Learn Site documentation for the following use cases:

• [ ] How to create models and annotate/describe them to use with the storage system.
• [ ] How to define configuration for creating collections using common create implementation.
• [ ] How to use record and collection management apis.
• [ ] How to implement your own collection create implementation for break glass scenario.
• [ ] How to implement your own mapper.
• [ ] How to upgrade from the current storage system to the new one.