HUE-1658 [oozie] Cron like scheduling

Replace old double dropdown by an text crontab.
Try to go convert old frequency format to the new crontab one.
Adding a new coordinator util lib as it needs to work on both edit and create
coordinator tab.

Dashboard should detect if the coordinator is using the crontab format and
try display it in english with the plugin (todo in another jira)
Choice was made to remove the previous form. Frequencies like every 3 days
is a bit more complicated are not supported by the plugin and some like
every 2 days are not supported by cron AFAIK.

Maybe add the advanced options to use the old dropdown.
HUE-1658 [oozie] Shifting Sunday to first week day

Minor UX changes
HUE-1658 [oozie] Adding backward compatibility flag

Set this to false to use the old frequency representation instead of the crontab.

[oozie]
  # Use Cron format for defining the frequency of a Coordinator instead of the old frequency number/unit.
  editor_coordinator_use_cron=false