Bug 20525: Add --timezone switch to koha-create

Bug 20525: Add --timezone switch to koha-create

This patch adds a --timezone switch to koha-create so the timezone can
be set on creation time. It defaults to empty (i.e. using the server's
local time).

To test:
- Create an instance:
  $ sudo koha-create --create-db timezone1
=> SUCCESS: /etc/koha/sites/timezone1/koha-conf.xml contains an empty
<timezone> entry.
- Apply this patch
- Run:
  $ perl misc4dev/cp_debian_files.pl
- Create a new instance:
  $ sudo koha-create --create-db timezone2
=> SUCCESS: /etc/koha/sites/timezone2/koha-conf.xml contains an empty
<timezone> entry (i.e. the current behaviour is preserved).
- Create a new instance:
  $ sudo koha-create --create-db --timezone Your/Timezone timezone3
=> SUCCESS: /etc/koha/sites/timezone3/koha-conf.xml contains
    <timezone>Your/Timezone</timezone> (i.e. introduced behaviour works)
- Sign off :-D

Sponsored-by: ByWater Solutions
Signed-off-by: Mark Tompsett <mtompset@hotmail.com>
Signed-off-by: Kyle M Hall <kyle@bywatersolutions.com>
Signed-off-by: Jonathan Druart <jonathan.druart@bugs.koha-community.org>