Add option to use DefaultAzureCredential for Azure BlobFileStore

[mariojsnunes]

Is your feature request related to a problem? Please describe.

Using a Managed Identity (DefaultAzureCredential) is safer than using connection strings. Also allows to use RBAC to control access.

Describe the solution you'd like

A simple solution would be to add a boolean flag UseDefaultAzureCredential to BlobStorageOptions and instantiate the BlobFileStore according to it.
Or could have a more flexible solution similar to Azure KeyVault .AddOrchardCoreAzureKeyVault(new DefaultAzureCredential())

[Piedone]

Is this something you'd venture into contributing if I help with pointers?

[mariojsnunes]

Yes I'd be happy to

[Piedone]

Great! Some suggestions:

• I'd add a new ManagedIdentityClientId property to MediaBlobStorageOptions and possibly BlobShellStorageOptions. Not BlobStorageOptions because the Azure Image Cache of ImageSharp doesn't support it, and thus the corresponding OC feature to be merged under Adding Azure and AWS-specific Image Caches of ImageSharp (Lombiq Technologies: OCORE-136) #15028 doesn't either. There's nothing else to store for this feature, right? Or not even that, and we only really need a boolean flag?
• Be sure to update the docs, see https://docs.orchardcore.net/en/latest/docs/topics/docs-contributions/.

[rjpowers10]

Maybe related? #12874

[mariojsnunes]

yep it is

[Piedone]

Indeed, this is a duplicate of #12639.