Fish: Fix prompt for fish v3.4.1

Removed my own copy of prompt_pwd because fish keeps saying "-d: unknown
option". I hadn't changed anything in the function anyway, so it should
just use the built-in one in /usr/share/fish/functions and it should
work as before.
Scripts: Add yadm install/upgrade script

Before setting up dotfiles, you can just:

curl https://hedy.tilde.cafe/scripts/install_yadm | bash

^that script is symlink'ed to this
Scripts: Forgot to add nvm install script
Scripts(setup/nvim): Quit if nvim not installed
Scripts: Use `cd - > /dev/null`

So `cd -` doesn't print the path everytime
Scripts(vim/nvim): Use +qall for (n)vim calls

Sad how I hadn't discovered thsi earlier. Had been use `:q` manually all
the time! :facepalm:
Scripts(gen/localfiles): Use a loop and only touch(1) if needed
Fish: Fix ls function on NetBSD

Apparently `ls ''` shows an error:

ls: no such file or directory

Nvim(ftplugin:fish): Fix comment lol

Imagine coding too much in python/sh and too little in vimL
Scripts(shltag): Add -f option for git tag -f

Recently had some drama in mucking up gelim tags so I had no choice but
to improve my tooling.
Fish: Add env stuff for nvm
Nvim(ftplugin:fish): Always use 4 spaces for indentation

Also see previous commit
Fish: Make all tabs become spaces :P

With a tab stop of 4, of course.
Fish: Don't use -GF for ls on NetBSD
Git: Add unstage and modify commit* aliases

Also add a coops because I found that I use it quite often.
Scripts(nvim): Check nvim existence and optionally upgrade vim-plug
Scripts: Modify friendly output in setup/aerc
Scripts: Fix upgrading diffsofancy & Vundle in install/misc
Scripts: Put localfiles under gen/ instead of setup

And add creation of ~/.addpath_local
Scripts: Rename install/all to install/misc

Because all isn't all