Add managed identity and service principal authentication in Azure Go blob service client

[ion-elgreco]

Managed identity and SP authentication is safer than access keys, it would be great if we can use those to authenticate, since we already use that for LakeFS anyways.

It's now not possible to use Azure client in Lua hooks with proper security in place.

[ozkatz]

We plan on introducing support for secret management for hooks. Managed identity means users will be able to leverage the existing identity attached to lakeFS which could lead to security exposure (privilege escalation).