pgAdmin 4 commit: Miscellaneous fixes for icon sizing issue, missing tr

Miscellaneous fixes for icon sizing issue, missing tree nodes to be
webpacked, etc.

- Fixed the background-size for the svg icons to 20x20 px such that it
does not adjust it's size when a context menu height is different due
to length of the node label, also - it allows us to fix the issue of
icons sizes in the Grant Wizard.

- Added two missing browser tree nodes in the webpack configuration
i.e. Foreign Server, and User Mapping
- Removed a redundant javascript file foreign-server.js
- Fixed the missing context menu icons for Foreign Table, and Tablespace
nodes.

Thanks EDB development team to find the regression added after the icon
changes in quick time.

Branch
------
master

Details
-------
https://git.postgresql.org/gitweb?p=pgadmin4.git;a=commitdiff;h=8c8c0e78cae7e4be1c171f58fe8973b3e248d90c

Modified Files
--------------
.../domain_constraints/css/domain_constraints.css | 3 +
.../foreign_tables/static/js/foreign-table.js | 719 ---------------------
.../foreign_tables/static/js/foreign_table.js | 10 +-
.../check_constraint/css/check_constraint.css | 2 +
.../templates/foreign_key/css/foreign_key.css | 6 +
.../tables/rules/templates/rules/css/rule.css | 1 +
.../triggers/templates/trigger/css/trigger.css | 3 +
.../schemas/views/templates/mview/css/mview.css | 1 +
.../schemas/views/templates/view/css/view.css | 2 +-
.../databases/templates/databases/css/database.css | 2 +
.../templates/pga_schedule/css/pga_schedule.css | 1 +
.../servers/pgagent/steps/__init__.py | 17 +
.../steps/templates/pga_jobstep/css/pga_step.css | 2 +
.../pgagent/templates/pga_job/css/pga_job.css | 2 +
.../servers/roles/templates/role/css/role.css | 4 +
.../servers/tablespaces/static/js/tablespace.js | 4 +-
.../servers/templates/css/server_type.css | 1 +
.../servers/templates/css/servers.css | 3 +
.../browser/templates/browser/css/collection.css | 1 +
web/pgadmin/browser/templates/browser/css/node.css | 2 +
web/webpack.config.js | 2 +
21 files changed, 61 insertions(+), 727 deletions(-)