Additional json output for mise doctor and mise env

[hverlin]

Hi, would it be possible to add json output for more commands?

• mise doctor --json (this would allow one to extract settings, dirs, warnings, ...)
• mise env --json exists, however it does not indicate which config file was used to load each environment variable (like mis ls --json or mise tasks --json). Can we add another option to this command to indicate where the variable comes from?

[hverlin]

For mise doctor, I think the only thing that's needed are the state directories (otherwise, everything is exposed through other commands like version, backends, plugins, settings...

One can use a similar logic as in the code to get the state dirs, though just wondering if having a hidden command to get them as json would work (maybe mise dirs --json)? I can create a PR

(unless mise doctor --json is better?)

The main reason is to know where the shims are located without to parse mise doctor output