[feature]: British English date and language support

Is there an existing issue for this?

• I have searched the existing issues

Summary

I wish to have the option to start my calendar week on a Monday and display dates in the format of DD/MM/YYYY. British spellings are welcomed but not as urgently needed as the date format support.

Why should this be worked on?

I find it very strange to see a week starting on Monday, and American dates will potentially cause confusion. Most teams based in the UK will probably feel the same if they switch to _Plane_, as almost all products they now use (Jira, Microsoft Office including Teams and Calendar) display dates in british date format. For this reason, it would be very hard to persuade the wider team to tranition to _Plane_.