Add release notes for tacker conductor and mistral vim monitoring

Change-Id: I3c5ac72a86595b4356451bb4c490b7367e88c97e
Implements: blueprint refactor-vim-monitor

releasenotes/notes/tacker-conductor-189281e2b6467b76.yaml

@@ -0,0 +1,7 @@
+---
+features:
+  - |
+    The component tacker-conductor is introduced for tacker mistral actions
+    to execute policy actions on tacker side. The conductor is listening on
+    TACKER_CONDUCTOR queue ( in the rabbitmq terms). Mistral actions RPC
+    calls the conductor.

releasenotes/notes/tacker-vim-monitoring-in-mistral-9e4710fcd1db5bc3.yaml

@@ -0,0 +1,10 @@
+---
+features:
+  - |
+    Vim monitoring via mistral workflow is used to replace old in-place vim
+    monitoring in tacker server.
+    Mistral is an integral part of tacker MANO system. To make full use of it,
+    and make the tacker server scale well, the feature creates a mistral
+    workflow and execute it. The mistral workflow action task then monitors
+    ( currently, pings) the vim, and notifies the tacker conductor to
+    update the VIM status.