inbound: Support multiple authorization types

[olix0r]

The inbound policy module uses the label saz_name to indicate the
authorization resource being employed to allow/deny traffic. This
corresponds to the ServerAuthorization kubernetes resource (with the
saz shortname). This resource type is going to be deprecated in favor
of a new, more general, AuthorizationPolicy resource.

When this change is made in the control plane, the policy controller
will include a kind label on gRPC messages indicating whether the
resource type, or default if a default policy is in effect.

This change honors this new kind field and adds a dedicated label to
indicate the kind.

Server labels are changed from:

srv_name="default:foo"
srv_name="fah"

to:

srv_kind="default",srv_name="foo"
srv_kind="server",srv_name="fah"

Authorization labels are changed from:

saz_name="default:bar"
saz_name="bah"

to:

authz_kind="default",authz_name="bar"
authz_kind="serverauthorization",authz_name="bah"

Signed-off-by: Oliver Gould [email protected]

[hawkw]

this looks good to me!