Update vim mode

[robsimmons]

Vim mode on Linux (http://c0.typesafety.net/doc/c0-at-andrew.html#vim) should be standardized into the C0 distribution and there should be a configuration script like the Emacs configuration script that hooks up C0 in Vim appropriately.

[ishantheperson]

Not sure what happened to vim but we have a LSP for vscode now: https://marketplace.visualstudio.com/items?itemName=15122staff.c0-lsp