Handling variables in the watched URL

@todo update

Sometimes you need to insert the current date

https://changedetection.io/test.txt?date={% now 'Europe/Berlin', '%d' %}.{% now 'Europe/Berlin', '%m' %}.{% now 'Europe/Berlin', '%Y' %}

Would request (according to the Europe/Berlin) timezone

https://changedetection.io/test.txt?date=24.10.2022

List of accepted timezones https://en.wikipedia.org/wiki/List_of_tz_database_time_zones

List of date format codes (the %d etc) https://docs.python.org/3/library/datetime.html#strftime-and-strptime-format-codes