[pgAdmin][RM4006] Trigger enable always/replica shown as disabled

Hi Hackers,

Attached is the patch for Bug-cum-feature to show always/replica options
for triggers.
The "Trigger enabled" switch control is changed to select2 dropdown now,
with four options as Enable, Enable Replica, Enable Always, Disable.
Changes are done for both triggers and compound triggers(EPAS v12+). The
context menu options of Enable/Disable trigger will work as before.
Docs are updated and test cases are updated accordingly.

Kindly review.

-- 
Thanks and Regards,
Aditya Toshniwal
Sr. Software Engineer | EnterpriseDB India | Pune
"Don't Complain about Heat, Plant a TREE"