pgAdmin 4 commit: Use on-demand loading for results in the query tool.

Use on-demand loading for results in the query tool. Fixes #2137

With a 27420 row query, pgAdmin III runs the query in 5.873s on my laptop. pgAdmin 4 now takes ~1s.

Branch
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master

Details
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https://git.postgresql.org/gitweb?p=pgadmin4.git;a=commitdiff;h=c65158312d6db6425abfde67d4f228910af223c3
Author: Harshal Dhumal <harshal(dot)dhumal(at)enterprisedb(dot)com>

Modified Files
--------------
web/config.py | 6 +
.../connect_to_server_feature_test.py | 4 +
.../feature_tests/pg_datatype_validation_test.py | 46 +-
web/pgadmin/feature_tests/query_tool_tests.py | 734 ++++++++++++++++++++
web/pgadmin/feature_tests/view_data_dml_queries.py | 25 +-
.../xss_checks_panels_and_query_tool_test.py | 17 +-
.../xss_checks_pgadmin_debugger_test.py | 1 +
web/pgadmin/static/bundle/slickgrid.js | 1 +
web/pgadmin/static/js/selection/column_selector.js | 22 +-
web/pgadmin/static/js/selection/copy_data.js | 6 +-
web/pgadmin/static/js/selection/grid_selector.js | 31 +-
.../js/selection/range_boundary_navigator.js | 4 +-
web/pgadmin/static/js/selection/row_selector.js | 3 +-
web/pgadmin/static/js/selection/set_staged_rows.js | 41 +-
.../static/js/slickgrid/slick.pgadmin.editors.js | 34 +-
web/pgadmin/tools/sqleditor/__init__.py | 321 ++++++---
web/pgadmin/tools/sqleditor/command.py | 137 ++--
.../tools/sqleditor/static/css/sqleditor.css | 11 +-
.../sqleditor/templates/sqleditor/js/sqleditor.js | 762 +++++++++++----------
web/pgadmin/utils/driver/abstract.py | 14 +-
web/pgadmin/utils/driver/psycopg2/__init__.py | 86 ++-
web/regression/feature_utils/pgadmin_page.py | 33 +-
.../javascript/selection/copy_data_spec.js | 24 +-
.../selection/range_boundary_navigator_spec.js | 22 +-
.../javascript/selection/row_selector_spec.js | 12 +-
.../javascript/selection/set_staged_rows_spec.js | 373 +++++-----
.../selection/xcell_selection_model_spec.js | 9 +-
.../handle_query_output_keyboard_event_spec.js | 23 +-
28 files changed, 1934 insertions(+), 868 deletions(-)