In _set() method, getting acos-version and using payload for cert and key as per the version requirement.
In case of update(), if acos-version >= 5.2.1, passing existing as well as new certificate-list as payload params, as it is required for the update operation in acos 5.2.1 at this moment.
Description
Used different SSL aXAPI based on ACOS version.
Technical Approach: