pgAdmin 4 commit: Infrastructure and changes to the Query Tool forreal

Infrastructure and changes to the Query Tool for realtime preference handling. Refs #3294

Highlights of this patch include:
- Changes will affect SQL Editors in Create dialog boxes, SQL tab of the main screen, Query tool, History entries in
thequery tool, Query tool opened in New Tab/Window 
- All the components of SQL editor will refer to single source of preferences which is cached in the Browser object.
Allother redundant ajax get preference calls are removed. 
- SQL editor will not refer template JS variables anymore, once all the references are removed the template variables
willalso be removed. 
- Code refactoring wherever possible.
- Covered JS test cases wherever possible.

Branch
------
master

Details
-------
https://git.postgresql.org/gitweb?p=pgadmin4.git;a=commitdiff;h=bdb7e3fde2ff3e3895181469ce24d533e5c7cfbf
Author: Aditya Toshniwal <aditya.toshniwal@enterprisedb.com>

Modified Files
--------------
web/pgadmin/browser/__init__.py                    |  11 -
web/pgadmin/browser/static/css/browser.css         |   7 +
web/pgadmin/browser/static/js/browser.js           |  71 +---
web/pgadmin/preferences/static/js/preferences.js   |  12 +-
web/pgadmin/static/js/backform.pgadmin.js          |  73 +++-
web/pgadmin/static/js/keyboard_shortcuts.js        |  66 ++-
.../static/js/sqleditor/query_tool_actions.js      |  52 ---
web/pgadmin/static/js/sqleditor_utils.js           |  27 +-
.../static/jsx/history/detail/code_mirror.jsx      |   5 +
.../jsx/history/detail/history_detail_query.jsx    |   2 +
web/pgadmin/static/jsx/history/query_history.jsx   |   5 +-
web/pgadmin/static/jsx/react_shapes.jsx            |   6 +
web/pgadmin/tools/datagrid/__init__.py             |  40 +-
web/pgadmin/tools/datagrid/static/js/datagrid.js   |  38 +-
.../tools/datagrid/templates/datagrid/index.html   |  93 ++---
.../tools/sqleditor/static/css/sqleditor.css       |  16 +
web/pgadmin/tools/sqleditor/static/js/sqleditor.js | 445 +++++++--------------
.../tools/sqleditor/tests/test_pref_utilities.py   | 100 -----
.../sqleditor/utils/query_tool_preferences.py      | 120 ------
.../javascript/history/query_history_spec.jsx      |  15 +-
.../sqleditor/keyboard_shortcuts_spec.js           | 141 ++++---
web/regression/javascript/sqleditor_utils_spec.js  |   8 +
web/webpack.shim.js                                |   2 +
web/webpack.test.config.js                         |   1 +
24 files changed, 517 insertions(+), 839 deletions(-)