pgAdmin 4 commit: Improvements in the form/properties dialog control ge

Improvements in the form/properties dialog control generation, and data
change events.

- In input & textarea control, call the change event on key up (but -
  not on every key up events, wait for sometime before trigger that
  event, so that - we do not overdo that).
- In unique/subnode control, whenever we create new model object, set
  all the required static fields used by pgAdmin form generation logic.
- In NodeAjaxListCell, we don't need to call the list generation
  operation (ajax operation) for each and every cell. They use the same
  shared column object.

Branch
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master

Details
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http://git.postgresql.org/gitweb?p=pgadmin4.git;a=commitdiff;h=b52a5736ff137f057f720e8ad18559f663bdb28f

Modified Files
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web/pgadmin/browser/static/js/node.ui.js  | 44 ++++++++-------
web/pgadmin/static/js/backform.pgadmin.js | 89 +++++++++++++++++++------------
2 files changed, 77 insertions(+), 56 deletions(-)