HUE-1909 [impala] No errors are displayed

In both Impala/Beeswax:
- create table already exists three times
- create aaaaaaa thre times
- one multiple query three times: show tables, create aaaaaa, select * from sample_07
- explaine with good and bad synxtax several times
[beeswax] force scroller to work

Add logic to retry scroller until it resizes.
HUE-1915 [core] MultipleObjectsReturned for tags or permissions

Only a strict unique clause in a DB could prevent duplicate tags or permissions
to be created. We clean them up at access time instead of filing as it is safe
to delete the duplicates.

Strick DB that fails when installing the Hue example should click on each individual
example install insteaf of the install all button.
[core] Improve logging timezone information
HUE-1908 [beeswax] Database of a saved query is not loaded back when opening it

Need specific logic for different states: query history, design, and execute query.
If query history or design, need to wait for databases and design/query to load.
Otherwise, just need to wait for databases to load.
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
Merge remote-tracking branch 'remotes/origin/testing' into testing