Mix different locales, e.g. Language and Date

### Your use case

#### What would you like to do?
I want to use English (US) language but German (DD.MM.YYYY) or Danish (YYYY-MM-DD) date locale.

#### Why would you like to do it?
As international person I might be used to one language in-app, e.g. if I was working remote at an international company like Element and write English with my contacts, the UI being in another language can be confusing. However now I'm stuck with that language's locale also.

#### How would you like to achieve it?
Additional dropdown for date locale in General -> Language & Region settings

### Have you considered any alternatives?

It would be perfect if E desktop would simply use my system locale, which already supports this configuration.

### Additional context

_No response_