Change \conninfo to use tabular format

Change \conninfo to use tabular format

(Initially the proposal was to keep \conninfo alone and add this feature
as \conninfo+, but we decided against keeping the original.)

Also display more fields than before, though not as many as were
suggested during the discussion.  In particular, we don't show 'role'
nor 'session authorization', for both which a case can probably be made.
These can be added as followup commits, if we agree to it.

Some (most?) reviewers actually reviewed rather different versions of
the patch and do not necessarily endorse the current one.

Co-authored-by: Maiquel Grassi 
Co-authored-by: Hunaid Sohail 
Reviewed-by: Nathan Bossart 
Reviewed-by: Peter Eisentraut 
Reviewed-by: Sami Imseih 
Reviewed-by: David G. Johnston 
Reviewed-by: Jim Jones 
Reviewed-by: Tom Lane 
Reviewed-by: Pavel Luzanov 
Reviewed-by: Dean Rasheed 
Reviewed-by: Erik Wienhold 
Discussion: https://postgr.es/m/CP8P284MB24965CB63DAC00FC0EA4A475EC462@CP8P284MB2496.BRAP284.PROD.OUTLOOK.COM