Strip vim entirely; EDITOR is nano

dissimulo does not use vim. Removes the editor, its config tree, its plugin
manager, and everything that would reinstall it on a re-bootstrap.

Deleted (82 files):
  vim/ (64)          the whole config tree, 1.7M
  doc/vim/ (8)       its documentation
  .vimrc, vimrc, .vim
  bin/yadr/vundle.rb, yadr-vim-{add,delete,list}-plugin
  bin/fix_macvim_external_display.sh   MacVim on macOS, dead here anyway
  vimify/            vi keybindings for readline/libedit, dropped on request

Edited:
  Rakefile        drop the vundle require, the vim install block, the
                  vundle_migration and install_vundle tasks, their two helper
                  methods, and the macvim homebrew line. Without this a
                  re-bootstrap would pull all of it straight back.
  install.sh      .vim/.vimrc out of the symlink list
  zsh/vi-mode.zsh EDITOR/VISUAL now nano. The zsh vi keybindings stay; they
                  are not vim.
  zsh/aliases.zsh yav/ydv/ylv, the MacVim detection block and ve removed;
                  ae/ze/gi now open nano
  git/gitconfig   mvimdiff mergetool removed, editor set to nano
  .tmux.conf      vim-tmux-navigator replaced with direct select-pane binds.
                  It ran ps piped to grep on EVERY C-h/j/k/l press to ask
                  whether vim held the pane: two forks per pane switch for a
                  question that can now only answer no. mode-keys and
                  status-keys vi stay, being tmux own key style, unrelated to
                  the editor.
  .gitignore/.dockerignore/Dockerfile   dead paths and the vim package

Also renames the installer banner to DRUNKENDOTFILES, piped through lolcat
when present with a plain-text fallback.

Left alone: the .yadr paths (renaming the checkout is a separate job), generic
swap-file ignores, the fasd viminfo support (third-party), and prose mentions.

install.sh

@@ -26,7 +26,7 @@ PERSONAL_FILES=(
   # Relative symlinks into .yadr/... — YADR's rake install creates equivalents,
   # but we deploy these too so things work even if rake install is skipped.
   .aprc .ctags .editrc .escaped_colors.rb .gemrc .gitconfig .inputrc .pryrc
-  .rdebugrc .unescaped_colors.rb .vim .vimrc .zlogin .zlogout .zpreztorc
+  .rdebugrc .unescaped_colors.rb .zlogin .zlogout .zpreztorc
   .zprofile .zshenv .zshrc
 )
 
@@ -77,7 +77,7 @@ cd "$YADR_DIR"
 log "Ensuring submodules are initialized"
 git submodule update --init --recursive
 
-# 2. Run YADR's native install (Vim plugins, prezto, etc.)
+# 2. Run YADR's native install (prezto, etc.)
 if have rake; then
   log "Running YADR rake install"
   [ "${1:-}" = "ask" ] && export ASK="true"