Handle the hardcoded configuration values

This patch allows to customize the hardcoded configuration values,
as well as introduce new multiline configuration options for keystone
service by configmap template:

  keystone:
    server:
      configmap:
        DEFAULT:
          debug: true
          rate_limit_except_level: debug
        auth:
          methods: 'external,password,token'
        tokenless_auth:
          trusted_issuer: 'O=Mirantis,L=Prague,CN=Salt Master CA,C=cz'

  keystone:
    server:
      configmap:
        tokenless_auth:
          trusted_issuer:
            type: 'MultiOpt'
            values:
              value1: 'O=Mirantis,L=Prague,CN=Salt Master CA,C=cz'
              value2: 'O=Mirantis,L=Kharkiv,CN=Salt Master CA2,C=ua'

Change-Id: I9c932e76a4e29e8e294c56354687714251f4b3bc
Related-Prod: PROD-29040
diff --git a/README.rst b/README.rst
index a517681..957c72a 100644
--- a/README.rst
+++ b/README.rst
@@ -974,6 +974,40 @@
                   lock_password: True
 .. code-block::
 
+Keystone configmap setup:
+---------------
+# Default type:
+.. code-block:: yaml
+
+  keystone:
+    server:
+      configmap:
+        DEFAULT:
+          debug: true
+          rate_limit_except_level: debug
+        auth:
+          methods: 'external,password,token'
+        tokenless_auth:
+          trusted_issuer: 'O=Mirantis,L=Prague,CN=Salt Master CA,C=cz'
+
+.. code-block::
+
+
+# type: 'MultiOpt' for multiline values:
+.. code-block:: yaml
+
+  keystone:
+    server:
+      configmap:
+        tokenless_auth:
+          trusted_issuer:
+            type: 'MultiOpt'
+            values:
+              value1: 'O=Mirantis,L=Prague,CN=Salt Master CA,C=cz'
+              value2: 'O=Mirantis,L=Kharkiv,CN=Salt Master CA2,C=ua'
+
+.. code-block::
+
 Upgrades
 ========