aix: install rust

[abmusse]

Add rust, cargo, and rustfmt to the lsit of packages to install.

[richardlau]

It looks like on AIX, cargo/rustc are not installed into /opt/freeware/bin so are not on the PATH, e.g. https://ci.nodejs.org/job/node-test-commit-aix/61998/nodes=aix72-power9/console

It looks like they are in /opt/freeware/lib/RustSDK/1.88/bin. We either need to:

• Add this path to the PATH in the Jenkins start script:

  build/ansible/roles/jenkins-worker/templates/aix.rc2.j2

  Line 20 in 522b933

  export PATH="/opt/freeware/bin:/usr/opt/python3/bin/:$PATH"; \

• Add the path into select-compiler.sh for AIX.
• Export CARGO and RUSTC environment variables in select-compiler.sh for AIX with fully qualified paths to cargo/rustc.
• Create symlinks in /opt/freeware/bin to cargo/rustc (i.e. the symlinks would be on the PATH).