pgAdmin 4 commit: Fix syntax error when creating new pgAgentschedules

Fix syntax error when creating new pgAgent schedules with a start
date/time and exception. Fixes #3638

- Fixed syntax error.
- Update/Delete exceptions are not working, SQL is wrong.
- Wrong exception time is shown, it should shown in UTC as datatype of
  the column is timestamp with out timezone.
- Added test cases for Schedule and Steps of pgAgent Job.

Branch
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master

Details
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https://git.postgresql.org/gitweb?p=pgadmin4.git;a=commitdiff;h=50738db2b8c871869a37c0b7617687bd4efd9da3
Author: Akshay Joshi <akshay.joshi@enterprisedb.com>

Modified Files
--------------
.../pgagent/schedules/static/js/pga_schedule.js    |  14 +-
.../pgagent/templates/macros/pga_exception.macros  |   8 +-
.../pgagent/templates/macros/pga_schedule.macros   |   2 +-
.../templates/pga_schedule/sql/pre3.4/create.sql   |   6 +
.../pgagent/tests/tests_pgagent_add_schedule.py    |  80 +++++++
.../pgagent/tests/tests_pgagent_add_steps.py       |  69 ++++++
.../pgagent/tests/tests_pgagent_delete_schedule.py |  52 +++++
.../pgagent/tests/tests_pgagent_delete_steps.py    |  52 +++++
.../pgagent/tests/tests_pgagent_put_schedule.py    | 131 ++++++++++++
.../pgagent/tests/tests_pgagent_put_step.py        |  67 ++++++
.../server_groups/servers/pgagent/tests/utils.py   | 235 ++++++++++++++++++++-
11 files changed, 703 insertions(+), 13 deletions(-)