This change enables the setting of import mode through the image config API which is then synced to the apiserver's observed config which then enables apiserver to set the import mode based on this value. The import mode in the observed config is also populated by default based on the payload type

• single => Legacy
• multi => PreserveOriginal

poc: https://github.com/Prashanth684/api/commit/c660fba709b71a884d0fc96dd007581a25d2d17a