[tz] Add option to act like global-tz

[Robert Elz]

    Date:        Mon, 15 Aug 2022 21:36:52 +0100
    From:        Stephen Colebourne via tz <tz at iana.org>
    Message-ID:  <CACzrW9CP9w5SMUX=Er7ana2dyGn4oW0T18HB+mG6-Hg_kwdy_w at mail.gmail.com>

I am going to try this off list, but it looks as if joda.org mail
goes to gmail, in which case it is 99% certain that the message will
never make it to you (Google don't like my attitudes wrt e-mail and
the takeover by the major e-mail providers - they bounce almost all
mail from munnari.oz.au).

As I expected, that failed - something called mx.kundenserver.de received
the message, then tried forwarding to gmail, which rejected the message.

So apologies to people on the list who didn't really need to see this.

  | Robert, if there is something specific about global-tz that is "wrong"

I would have preferred if the comments from backzone moved back to the
original files, along with the data - the way it was done for 2022agtz
but it worked as it was, in general.

kre