Add different types of authentication for azure blob storage

[pondzix]

This PR makes azure blob storage more flexible regarding authentication methods. Now t's possible to configure multiple storage accounts (like before), but with:

• no authentication at all. No credentials are used when accessing storage. Useful for public accounts.
• authentication using default credentials chain. That's the method Enrich used previously for all configured accounts.
• authentication using SAS token. Token is provided in configuration and NOT generated dynamically in application.

New configuration looks like:

    "azureStorage": {
      "accounts": [
        # Example public account with no auth
        { "name": "storageAccount1"},

        # Example private account using default auth chain -> https://learn.microsoft.com/en-us/java/api/com.azure.identity.defaultazurecredential?view=azure-java-stable
        { "name": "storageAccount2", "auth": { "type": "default"} },

        # Example private account using SAS token auth
        { "name": "storageAccount3",  "auth": { "type": "sas", "value": "tokenValue"}}
      ]
    }

Comparing to the old one:

    "azureStorage": {
      # Azure blob storage account names
      "storageAccountNames": ["storageAccount1", "storageAccount2"]
    }