Managers ID : Introduced variable to declare Managers ID in resource.robot and updated all the scripts in openbmc-test-automation

Changes:
    - Introduced ${MANAGER_ID} variable in resource.robot
    - Replaced all the Managers/bmc to Managers/${MANAGER_ID} across all the scripts
    - Also in data/variables.py updated chassis id for the few redfish uri.

Tested:
     - Ran All The Scripts Successfully

Change-Id: Iff3673aae27657e0799dec5cb94c1651a0cd5d18
Signed-off-by: ganesanb <ganesanb@ami.com>
Signed-off-by: George Keishing <gkeishin@in.ibm.com>
diff --git a/redfish/test_xit.robot b/redfish/test_xit.robot
index 57dd3fe..a5675e8 100644
--- a/redfish/test_xit.robot
+++ b/redfish/test_xit.robot
@@ -22,7 +22,7 @@
 
     # Check dump entry based on Redfish API availability.
     Redfish.Login
-    ${resp}=  Redfish.Get  /redfish/v1/Managers/bmc/LogServices/Dump/Entries
+    ${resp}=  Redfish.Get  /redfish/v1/Managers/${MANAGER_ID}/LogServices/Dump/Entries
     ...  valid_status_codes=[${HTTP_OK}, ${HTTP_NOT_FOUND}]
 
     Log To Console  ${resp}