Bug bash fixes to Azure Arc PostgreSQL (#20568)

* Added username field to PG and removed defaultvalue for port

* Disabled system username for miaa. Added username to pg create notebook.

* Block system for pg username

* Remove sql username from pg create

* Add service type

* bump version for preview

* Add dev use label

* Changed postgres icon

* Fixed PG create page not displaying. Wrong type

* Fixed service type

* changed naming for admin usernames sql and pg

* sql and pg dev use fix

* Move port under service type and make storage class not required

* Fixed regex to include things like sa1 system1

* Made storage class params optional

* Added placeholder text and changed PG admin username label

* Remove backups

* Removed postgres hardcoded username in connectionstring

* Remove more postgres username hardcoded

Co-authored-by: Candice Ye <canye@microsoft.com>

extensions/azcli/package.json

@@ -2,7 +2,7 @@
   "name": "azcli",
   "displayName": "%azcli.arc.displayName%",
   "description": "%azcli.arc.description%",
-  "version": "1.5.2",
+  "version": "1.5.3",
   "publisher": "Microsoft",
   "license": "https://raw.githubusercontent.com/Microsoft/azuredatastudio/main/LICENSE.txt",
   "icon": "images/extension.png",