Migrate ADX datasource to Kusto SDK

[kostrse]

Azure Data Explorer has official SDK for Go github.com/Azure/azure-kusto-go.

It may be beneficial to switch from own Kusto client implementation to the Kusto SDK.

Authentication

While Kusto SDK providers own authentication logic which doesn't align with Grafana Azure SDK. Technically it should be possible to write own implementation of azcore.TokenCredential interface which would work as an adapter and delegate token request to token provider of Grafana Azure SDK.