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/extended/code_update/bmc_code_update.robot b/extended/code_update/bmc_code_update.robot
index e0233ad..dbd3ef8 100644
--- a/extended/code_update/bmc_code_update.robot
+++ b/extended/code_update/bmc_code_update.robot
@@ -217,7 +217,7 @@
     Sleep  30s
 
     ${bmc_cert_content}=  redfish_utils.Get Attribute
-    ...  /redfish/v1/Managers/bmc/Truststore/Certificates/${cert_id}  CertificateString
+    ...  /redfish/v1/Managers/${MANAGER_ID}/Truststore/Certificates/${cert_id}  CertificateString
     Should Contain  ${cert_file_content}  ${bmc_cert_content}
 
     Upload And Activate Image  ${IMAGE_FILE_PATH}