pgAdmin 4 commit: Save the treeview state periodically,and restore it

Save the treeview state periodically, and restore it automatically when reconnecting. Fixes #1253

Branch
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master

Details
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https://git.postgresql.org/gitweb?p=pgadmin4.git;a=commitdiff;h=528ea88deceacd593fc9e92b083e03f3b849fba9
Author: Khushboo Vashi <khushboo.vashi@enterprisedb.com>

Modified Files
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docs/en_US/release_notes.rst                       |   1 +
docs/en_US/release_notes_3_5.rst                   |  18 ++
.../browser/register_browser_preferences.py        |  10 +
.../browser/server_groups/servers/__init__.py      |   3 +-
web/pgadmin/browser/static/js/browser.js           |  21 +-
web/pgadmin/browser/static/js/node.js              |  17 +-
web/pgadmin/browser/static/js/preferences.js       |   3 +
web/pgadmin/preferences/static/js/preferences.js   |   1 +
web/pgadmin/settings/__init__.py                   |  54 +++-
.../static/js/tree/pgadmin_tree_save_state.js      | 331 +++++++++++++++++++++
.../tree/pgadmin_tree_state_save_spec.js           | 242 +++++++++++++++
11 files changed, 680 insertions(+), 21 deletions(-)