Add OpenStack credential propagation support

[bnallapeta]

Local Run:

ka get machines
NAME                           CLUSTER         NODENAME                       PROVIDERID                                          PHASE     AGE     VERSION
openstack-dev-cp-0             openstack-dev   openstack-dev-cp-0             openstack:///b52ccc71-566b-4487-a0b8-64b2c08f0e5b   Running   8m29s   v1.30.5+k0s.0
openstack-dev-cp-1             openstack-dev   openstack-dev-cp-1             openstack:///4022efcb-da46-4a99-80f3-2eaf3681238e   Running   8m29s   v1.30.5+k0s.0
openstack-dev-cp-2             openstack-dev   openstack-dev-cp-2             openstack:///87ae87e0-2ac5-4f06-b7ba-970d6dbcab3f   Running   8m29s   v1.30.5+k0s.0
openstack-dev-md-p27j6-6wfn4   openstack-dev   openstack-dev-md-p27j6-6wfn4   openstack:///5c2c51c8-f2c0-48d3-9c8f-ed28db53112a   Running   8m30s   
openstack-dev-md-p27j6-w6qvx   openstack-dev   openstack-dev-md-p27j6-w6qvx   openstack:///2df39a6d-2507-452f-9a0a-fb3e6a5d2052   Running   8m30s   

clusterctl describe cluster openstack-dev -n hmc-system
NAME                                                      READY  SEVERITY  REASON  SINCE  MESSAGE                                                        
Cluster/openstack-dev                                     True                     5m26s                                                                  
├─ClusterInfrastructure - OpenStackCluster/openstack-dev                                                                                                  
├─ControlPlane - K0sControlPlane/openstack-dev-cp                                                                                                         
│ └─3 Machines...                                         True                     7m32s  See openstack-dev-cp-0, openstack-dev-cp-1, ...                 
└─Workers                                                                                                                                                 
  └─MachineDeployment/openstack-dev-md                    True                     110s                                                                   
    └─2 Machines...                                       True                     3m43s  See openstack-dev-md-p27j6-6wfn4, openstack-dev-md-p27j6-w6qvx  

k -n hmc-system get managedclusters.hmc.mirantis.com 
NAME            READY   STATUS
openstack-dev   True    ManagedCluster is ready

[a13x5]

Several issues with overall logic.
Also I believe the scope of this PR could be broaden a little bit by adding credential passing to the cluster (setIdentityHelmValues function). Currently we're expecting ClusterIdentity object only, this isn't the case with OpenStack provider, so logic should be adjusted/tested. If you prepared another PR with these changes it should be merged first.

[bnallapeta]

@a13x5 @eromanova Would appreciate if you can take a look at the PR and merge it soon.

[eromanova]

Small comment from my side. The rest looks good.

[a13x5]

Approved
Additional fixes will be made later