Azure DevOps provider support for workload identity connection

[miqm]

Hello,

Similar to the flux source controller (https://github.com/fluxcd/flux2/tree/main/rfcs/0007-git-repo-passwordless-auth), I'd like the notification controller to support connecting to Azure DevOps with Workload Identity that is assigned to the flux's notification controller pod(s).

Optionally, we could allow providing a clientId of the identity (that has configured federation of course) so we can use different identities on different repository references.