Card origin_runtime_255: Publish district uid limits to nodes [DO NOT MERGE]

    Add facts for district_first_uid and district_max_uid

    Update set_district mcollective action to record first_uid and
    max_uid

    Add set_district_uid_limits mcollective action to update first_uid
    and max_uid

    Update district model to update first_uid and max_uid when a node is
    added, removed, activated, deactivated or if the capactiy for a
    district is modified.