Adjust displayed mail-headers in my neomutt

Previously the headers-config was only applied to gmail-mailboxes (I
guess that was a mistake of my past). This change configures them for
all mailboxes.

Furthermore I dropped the x-mailer, since I'm really _not_ interested in
the sending mail-client...

Finally I adjusted the order of the headers, from the, sometimes,
awkward default-ordering to my own preferences.

Reference: http://www.fefe.de/muttfaq/muttrc

.config/mutt/gmail.muttrc

@@ -16,9 +16,6 @@ mailboxes =INBOX \
   -label Spam "=[Gmail]/Spam" \
   -label Archive "=[Gmail]/All Mail" \
 
-# Headers to show
-ignore *
-unignore date from to cc subject x-mailer resent-from reply-to
 bind pager,index d noop
 bind pager,index e noop