MCOL-5806: added ability to start node in read-only mode

* feat(cmapi): add read_only param for API add node endpoint
* style(cmapi): fixes for string length and quotes

Add dbroots of other nodes to the read-only node

On every node change adjust dbroots in the read-only nodes

Fix logging (trace level) in tests

cmapi/cmapi_server/test/test_cluster.py

@@ -6,6 +6,7 @@ from shutil import copyfile
 
 import requests
 
+from cmapi_server.constants import MCSProgs
 from cmapi_server.controllers.dispatcher import _version
 from cmapi_server.managers.process import MCSProcessManager
 from cmapi_server.test.unittest_global import (
@@ -199,7 +200,7 @@ class ClusterAddNodeTestCase(BaseClusterTestCase):
 
         # Check Columntore started
         controllernode = subprocess.check_output(
-            ['pgrep', 'controllernode'])
+            ['pgrep', MCSProgs.CONTROLLER_NODE.value])
         self.assertIsNotNone(controllernode)