High: iSCSILogicalUnit: monitor operation must pass before start is considered complete

In general it is a good idea to verify the monitor operation passes
before marking a resource as started. Here we have a technical reason
to do this as well, as this also helps verify some issues that can
occur with the targetcli implementation not providing non zero exit
codes during errors.
Low: iSCSILogicalUnit: support ocf exit reason string
Low: iSCSITarget: fix format inconsistency
Low: iSCSITarget: refactor stop logic to reduce indentation
High: iSCSITarget: monitor operation must pass before start is considered complete

    In general it is a good idea to verify the monitor operation passes
    before marking a resource as started. Here we have a technical reason
    to do this as well, as this also helps verify some issues that can
    occur with the targetcli implementation not providing non zero exit
    codes during errors.
Low: iSCSITarget: Support exit reason string