Feature request: Option to specify path to `cargo`

[hehaoqian]

Option to specify absolute path to cargo.
Or alternatively, option to specify the environment variable when run cargo,
so I can change PATH to select alternative cargo,
which I currently do in Rust analyzer

Rational:
Our project mixes use of C/C++, Python and Rust, with matrixes of target CPU and compiler toolchain.
Currently each configuration is setup by a bash script named cargo, which wraps the original cargo,
and setups needed environment variables for cargo.
So the cargo in the PATH when VSCode starts cannot be used.