prompt - Support multiple scopes

## Expected behaviour

https://github.com/conventional-changelog/commitlint/pull/901 added support for multiple scopes, but prompt and prompt-cli still doesn't understand them. It should support multiple scopes - both as step-by-step autocomplete as well as directly writing `a,b,c`.

## Current Behavior

In prompt-cli scope step, it doesn't allow values like `a,b`. Also no autocomplete.

## Affected packages

- [ ] cli
- [ ] core
- [X] prompt
- [ ] config-angular