CLI Command Syntax Design

Currently there's an ambiguity with
```sh
bliss list
```
where `list` could be interpreted as a command or a language. Currently it's a command, but whenever a language with the same name would appear (and conversely, if a new command named like an existing language appears) there could be some troubles with e.g. some scripts invoking `bliss`.

Commands and languages should be separated, possible options (please edit if you have other ideas):
1. hyphens, e.g. `bliss --cache` (bonus: shortened commands, i.e. `bliss -c`
2. argument for languages, e.g. `bliss --lang rust`
3. add a `lang` command, like this: `bliss lang rust,python`