* Issue 10209 - Remove read usages of zone
* Issue 10209 - Add coverage on daysSince and startOfDay cron utility functions
* Issue 10209 - Add unit test for daysUserHasMissed method
* Issue 10209 - Remove usages of deprecated `moment.js#zone` method.
* Issue 10209 - Add helper function to centralise logic
Also simplify timezoneOffsetToUtc function in site.vue
* Issue 10209 - Also add getUtcOffset as method on user
Co-authored-by: Matteo Pagliazzi <matteopagliazzi@gmail.com>