Support managed identity for chat storage table client and move out of host json

[maggie-li]

This PR adds support for managed identity with table storage, which is used to store chat history. This implementation has been tested to work with:

• System assigned managed identity on Azure
• User Assigned managed identity on Azure
• Local user account
• Connection string

Alongside the expected configs which can be found in the base README.md, here are the additional expected settings for each of the scenarios: For both system and user assigned a user must have:

"ChatStorage__tableServiceUri": "https://<>.table.core.windows.net"

System assigned managed identity on Azure:

• if neither resource id or client id is specified system assigned managed identity will be used

User assigned managed identity on Azure: "ChatStorage__credential": "managedidentity" "ChatStorage__managedIdentityResourceId" or "ChatStorage__managedIdentityClientId" but not both

Local user account:

"ChatStorage": "UseDevelopmentStorage=true" Connection string:

"ChatStorage": "<connection_string_to_desired_storage>"

To-do

• [x] Update the README.md to inform users of this change
• [x] Update the CHANGELOG.MD
• [ ] Create tests
• [x] Update other language samples
• [ ] - Update java samples - in a separate PR after publishing library changes

[manvkaur]

bump the package version in build.props and update CHANGELOG.md for this change

[manvkaur]

@microsoft-github-policy-service agree company="Microsoft"

[manvkaur]

This PR looks good. One thing I wanted to follow up on is if we're having tests for the managed identity vs connection string scenario?

Thank for reviewing this Aishwarya. Yes, I am creating mock unit tests for assistant service first and then other features slowly.