Add a `info` command about pixi

[baszalmstra]

Maybe something along the lines of: https://doc.rust-lang.org/cargo/commands/cargo-metadata.html

That would also make it machine readable. And usable by other tools.

What would you include in this info?

[ruben-arts]

As of right now I only needed it for finding out where the cache was stored and which virtual packages are available.

A machine readable version could be handy!

The cargo metadata is only specific to the package which can be a nice addition but I'm more interested in the system config.

[baszalmstra]

We could do something similar to docker info where you can specify --format and format it to your. There is a crate for that: https://github.com/fiji-flo/gtmpl-rust

[baszalmstra]

Related to #74

[wolfv]

Ideas for additional info elements:

• global
  • authentication store location (if fallback used)
  • global cache size?
  • last time repodata downloaded?
  • proxy settings (HTTP_PROXY / HTTPS_PROXY)
  • netrc files (if they are used by reqwest)
• project
  • number of packages installed
  • disk space used / size of .pixi folder
  • last time updated / locked
  • platforms that were locked