Replace mise-activate with simple wrapper scripts and ENV vars

The prompting for this change is to use mise within ksh/oksh without
having to rely on zsh (such as `zsh -c "mise activate zsh"` or
otherwise). I kind of like the simplicity of this, and then I can still
easily change versions as needed in a given project by sourcing a file
which exports different vars for target language versions, or I can just
do manual export commands from the shell.

src_files/.config/zsh/.zshrc

@@ -62,6 +62,5 @@ alias weather='curl "wttr.in/dfw?2&F"'
 alias shrug='echo "¯\\_(ツ)_/¯"'
 
 # programming and language setup
-[[ -n $(command -v mise) ]] && eval "$(mise activate zsh)"
 export DEVKITARM=/opt/devkitpro/devkitARM