Service account authentication for Mkube

[Alevsk]

Currently, Mkube support only bearer token authentication for secured endpoints,
clients that wishes to access resources behind a secured endpoint will need to provide
a jwt token using the HTTP Authorization header, ie:

curl --location --request GET 'http://localhost:8787/api/v1/tenants' --header 'Authorization: Bearer eyJ...'

The provided JWT token corresponds to the Kubernetes service account that Mkube will use to run tasks on behalf of the client
ie: list, create, edit, delete tenants, etc.

For local development you can use the jwt associated to the m3-sa service account, you can get the token running
the following command in your terminal:

kubectl get secret $(kubectl get serviceaccount m3-sa -o jsonpath="{.secrets[0].name}") -o jsonpath="{.data.token}" | base64 --decode

Then test the token works with curl

curl --location --request GET 'http://localhost:8787/api/v1/tenants' --header 'Authorization: Bearer eyJ...'
...
{
    "tenants": [
        {
            "creation_date": "2020-06-08 22:35:50 -0700 PDT",
            "currentState": "Ready",
            "instance_count": 4,
            "name": "minio",
            "volume_count": 16,
            "volume_size": 1099511627776,
            "zone_count": 1
        }
    ]
}

[cesnietor]

could you please remove all related models/ that are not used anymore and also the operations/user_api since those files are not deleted by swagger generator