Make `auditable` installs available in the `pixi-build-rust` backend

[ruben-arts]

Currently, the default install command on new rust packages in conda-forge is the auditable install which adds more metadata to the package.

The pixi-build-rust backends doesn't support setting that. To me the default should be:

• pixi install runs cargo install
• pixi build runs cargo auditable install

[baszalmstra]

Is the reason you dont want to do auditable by default because it adds overhead?