Bug 11678: Gather print notices: add --email parameter

Bug 11678: Gather print notices: add --email parameter

This patch add the ability to send generated files by email.

You can specify several emails.

Test plan:
- same as Bug 11603
- call the script misc/cronjobs/gather_print_notices.pl with the
  following parameters:

perl misc/cronjobs/gather_print_notices.pl /tmp/test --csv --ods --html
--letter_code=CHECKIN -d=: --email="email_one@example.org"
--email="email_two@example.org"

Signed-off-by: Frederic Demians <f.demians@tamil.fr>
  - Works as desribed. Rebased upon bug-11603.

Signed-off-by: Katrin Fischer <katrin.fischer.83@web.de>
Signed-off-by: Tomas Cohen Arazi <tomascohen@theke.io>