Add more roles to designate formulas

Provide roles:
pool_manager
worker
agent

The idea was proposed by Aleš Komárek:
https://gerrit.mcp.mirantis.net/6723

Make adjustments to designate.conf.Debian to be able
to take into account pool_manager changes in
reclass model.

Provide default roles description in pillars for tests.

Change-Id: I214d8db39365648b5ef9348b52edd839327ca197
Related-PROD: https://mirantis.jira.com/browse/PROD-14396
diff --git a/tests/pillar/designate_liberty.sls b/tests/pillar/designate_liberty.sls
index be528eb..bef5e4a 100644
--- a/tests/pillar/designate_liberty.sls
+++ b/tests/pillar/designate_liberty.sls
@@ -1,4 +1,6 @@
 designate:
+  pool_manager:
+    enabled: true
   server:
     enabled: true
     region: RegionOne
@@ -25,4 +27,4 @@
         uuid: f26e0b32-736f-4f0a-831b-039a415c481e
         options: 'port: 53, host: 127.0.0.1'
         masters: 127.0.0.1:5354
-        type:  bind9
\ No newline at end of file
+        type:  bind9