[pgAdmin][RM4818] Unable to handle loss of connection to server

Hi Hackers,

Attached is the workaround patch to set the default connection timeout to 30 seconds instead of the current value of infinite - 0, zero. The input is present in the server properties dialogs advanced tab. The workaround applies to the RM4724 as well.

The permanent solution would be to expand the nodes asynchronously - https://redmine.postgresql.org/issues/4933

Also fixed a bug where sql editor is not closing if the server is disconnected in between.

Kindly review.