azimuth: add sponsorship scry

pkg/arvo/app/azimuth.hoon

@@ -185,6 +185,7 @@
         [%x %nas ~]      ``noun+!>(nas.state)
         [%x %dns ~]      ``noun+!>(dns.nas.state)
         [%x %own ~]      ``noun+!>(own.state)
+        [%x %spo ~]      ``noun+!>(spo.state)
         [%x %refresh ~]  ``atom+!>(refresh)
         [%x %point @ ~]  ``noun+(point i.t.t.path)
     ==

pkg/arvo/app/roller.hoon

@@ -782,6 +782,16 @@
     (scot %da now.bowl)
     /own/noun
   ==
+::  +canonical-sponsors: current azimuth sponsorship
+::
+++  canonical-sponsors
+  .^  sponsors
+    %gx
+    (scot %p our.bowl)
+    %azimuth
+    (scot %da now.bowl)
+    /spo/noun
+  ==
 ::  +predicted-state
 ::
 ::    derives predicted state from applying pending & sending txs to
@@ -792,6 +802,7 @@
   ^-  (quip update _state)
   =:  pre  nas
       own  canonical-owners
+      spo  canonical-sponsors
     ==
   |^
   =^  [nes=_sending updates-1=(list update)]  state