Add basic monorepo-helpers for bash, fish, and zsh

[malfisya]

Summary

Add basic script to navigate the monorepo

[malfisya]

I only tested the bash script and the experience wasn't not starightforward. In Solus, I can just symlink the script to ~/.bashrc.d/ and it will just work. In Serpent, I have to copy the /usr/share/defaults/etc/profile to /etc/bashrc and added this line (mimiicking what Solus does in its equivalent file):

if [ -d ~/.bashrc.d ]; then
    for rc in ~/.bashrc.d/*; do
	if [ -f "$rc" ]; then
	    . "$rc"
	fi
    done
    unset rc
fi

I have not tested the zsh and fish script. Cheers!