Make the Logic App Connection better to Event Grid and Storage

[blgorman]

Step 6 - Logic App/Event Grid and Storage Integration

Currently the logic app uses the creator's login and the connection string to storage. This seems bad.

Consider trying:

• Use a Managed Identity to connect to storage
• Use a Managed Identity to connect to Event Grid
• Pre-create a user-assigned Managed Identity
• Assign the user-assigned MI on creation of the logic app

Not sure if that will work but those are my current thoughts