Bug 24455: Add JS functions to format date and datetime strings

Bug 24455: Add JS functions to format date and datetime strings

This patch adds the a js-date-format.inc file on each opac and staff interface (date-format.inc whas not available as name)

When you include that file in your TT, you'll get the following functions available:

1. $date(raw_date_string, options)

   This function parses a date string, as produced by an api call, and returns the corresponding date formatted according to 'dateformat' and 'TimeFormat' parameters.

   For example:

   // dateformat: us
   // timeformat: 12hr
   // Timezone: UTC

   $date('2020-03-23T15:00:00+01:00') // You will get '03/23/2020'

   $date('2020-03-23T15:00:00+01:00', {withtime: true}) // You will get '03/23/2020 14:00'

   $date('2020-03-23T15:00:00+01:00', {withtime: true, tz: 'Europe/Paris'}) // You will get '03/23/2020 15:00+01:00'

   Options:

   * dateformat: override date format as configured in staff interface (accepts also 'rfc3339')

   * timeformat: override time format as configured in staff client (available options are '12hr' and '24hr')

   * withtime: also print the time part (default false)

   * tz: set the timezone

2. $datetime(raw_date_string, option)

   The same as $date but sets withtime to true

3. $time(raw_date_string, option)

   The same as $datetime but shows only the time part

To test you must implement and test bug 20936, where it will be used

Signed-off-by: Andrew Isherwood <andrew.isherwood@ptfs-europe.com>
Signed-off-by: Kyle M Hall <kyle@bywatersolutions.com>
Signed-off-by: Martin Renvoize <martin.renvoize@ptfs-europe.com>