postgresql_server: new shiny template .conf file for postgresql 12
    
    I took the default postgresql.conf from postgresql 12 and then added in
    various changes we already manually made and variable substitions we
    already had setup back in the postgresq 9.2 days.
    
    This will apply to db-koji01, db-qa01, db-datanommer01 at least.
    
    Signed-off-by: Kevin Fenzi <kevin@scrye.com>