pgAdmin 4 commit: 1) Further styling tweaks for Dark Theme.

1) Further styling tweaks for Dark Theme.
2) Theme related code changes are removed from config.py and moved to miscellaneous under a new package - "themes".

Branch
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master

Details
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https://git.postgresql.org/gitweb?p=pgadmin4.git;a=commitdiff;h=c1c682402aca0cbd8fc5aa6c70b0221fb7ff93a6
Author: Aditya Toshniwal <aditya(dot)toshniwal(at)enterprisedb(dot)com>

Modified Files
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.gitignore | 2 +-
web/config.py | 19 -------
web/pgadmin.themes.json | 7 +++
web/pgadmin/__init__.py | 16 ++----
web/pgadmin/dashboard/static/js/charting.js | 4 ++
web/pgadmin/dashboard/static/scss/_dashboard.scss | 19 +++++--
web/pgadmin/misc/__init__.py | 9 ++--
web/pgadmin/misc/themes/__init__.py | 49 ++++++++++++++++++
web/pgadmin/static/js/backform.pgadmin.js | 2 +-
web/pgadmin/static/js/utils.js | 1 +
web/pgadmin/static/scss/_backgrid.overrides.scss | 19 +++++--
web/pgadmin/static/scss/_pgadmin.style.scss | 6 +--
web/pgadmin/static/scss/_webcabin.pgadmin.scss | 6 +--
.../static/scss/resources/_default.variables.scss | 21 ++++++--
.../scss/resources/_theme.variables.scss.sample | 8 +++
.../scss/resources/dark/_theme.variables.scss | 58 ++++++++++++----------
.../tools/datagrid/templates/datagrid/index.html | 2 +-
.../tools/sqleditor/static/css/sqleditor.css | 1 +
.../tools/sqleditor/static/scss/_sqleditor.scss | 27 ++--------
web/webpack.config.js | 2 +-
20 files changed, 171 insertions(+), 107 deletions(-)