I want to receive email messages from Kompassi in my own language

Current state: Some email templates are localized and some are not. For those that are, the source of the message language may not be the expected one.

For example:

1. Ticket sales receipts: UI language used by the customer to confirm the order
2. Program host invitations: UI language used by **the program manager** to send the invite

There is currently no concept of _preferred language of the user_.