[$] Key Rust concepts for the kernel

The first day of the online Kangrejos conference was focused on
introducing the effort to bring the Rust programming language into the
Linux kernel. On the second day, conference organizer Miguel Ojeda shifted
to presenting the Rust language itself with an emphasis on what Rust can
provide for kernel development. The result was a useful resource for
anybody who is curious about this project, but who has not yet had the time
to become familiar with Rust.