remove work-side local files

Reaching the limit of what useful non-confidential stuff I can put here
anyway.
vimrc: add Rust filetype detection
vimrc: minor wording tweak
vimrc: add bindings for 2-space/8-tab indentation

F2 switches to 2-space indentation, while F3 switches to 8-space tab
indentation. Mostly useful for working in C, in which I have to switch
between preferred and Linux kernel styles semi-frequently.