Massive update to gitconfig, add VISUAL to zshrc

Most of the gitconfig stuff is stolen from other dotfile repos out
there, wherein I perused their gitconfigs, saw things that looked like
good ideas, researched what they actually did, then added them.

Of particular importance is the removal of my gitconfig [user] block
which has been moved to an included local file. This is to get around
the fact that I use this repo for work and personal stuff and don't want
a default with my legal name or online identity in it.

.zshrc

@@ -11,6 +11,7 @@ source ~/.p10k/powerlevel10k.zsh-theme
 
 export PATH=~/bin:$PATH
 export EDITOR=vim
+export VISUAL=$EDITOR
 export PAGER=most
 
 HISTFILE=~/.zsh_history