pgAdmin 4 commit: 1) Added partition module in webpack config.

1) Added partition module in webpack config.
2) Fixed missing logic of partition from primary_key.js and unique_constraint.js as this two files are newly created
forwebpack. 
3) Changed the node name from 'check_constraint' to 'check_constraints'. Also changed the same in test case url.

Branch
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master

Details
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https://git.postgresql.org/gitweb?p=pgadmin4.git;a=commitdiff;h=a7f58e2b929a3c4143f74a3afb0c16aaa198da1e

Modified Files
--------------
.../constraints/check_constraint/__init__.py       |  2 +-
.../tests/test_check_constraint_add.py             |  2 +-
.../tests/test_check_constraint_delete.py          |  2 +-
.../tests/test_check_constraint_get.py             |  2 +-
.../tests/test_check_constraint_put.py             |  2 +-
.../index_constraint/static/js/primary_key.js      | 22 ++++++++++++--
.../static/js/unique_constraint.js                 | 20 ++++++++++---
.../tables/partitions/static/js/partition.js       | 34 +++++++++++-----------
web/webpack.config.js                              |  3 +-
9 files changed, 59 insertions(+), 30 deletions(-)