FEATURE: Use managed identities

[andriikaplanovskyi]

Use managed identities

Detailed Description

At this moment we use connection strings to provide access to:

• Azure SQL Database
• Azure File Storage
• Azure Service Bus

Instead to have a better level of security we can use managed identities for Azure resources. Some pieces of the foundation had already been created by the previous generations of Obelisk Core developers:

1. https://github.com/onebeyond/onebeyond-studio-core/commit/41beb574ca47132d52d50e2af1361bf8fc497feb

2. https://github.com/onebeyond/onebeyond-studio-core/commit/0d416b99089b6eaa0b9ebf1d718f192838511e04

we need to check if we can use the same idea to connecto the SQL database and to modify our terraform scrtipt to use managed identities when deploying Azure resources.

[nickskliar-davies]

@andriikaplanovskyi I've had issues with doing this with multiple users on some projects. It might be caused by users not "logging in" correctly, but this will need extended experimentation before rolling it out.