Hide prompts and masks that aren't in the set language

**Is your feature request related to a problem? Please describe.**
When pressing `/` to open the available prompts, or clicking on the `Mask` button, the page is filled with text in Chinese - which I'd love to be able to understand but I simply can't, so I am left with lots of scrolling. In the Masks section there is a way to filter by language, but this doesn't get saved.

**Describe the solution you'd like**
The settings page offer a `Language` dropdown. It would be ideal to have a tick box below that says "show me only prompts and masks in my language".