prompt.sh script

This script is composed of only one function precmd which is used by bash and zsh to compute the content of the prompt line to show.

It is sourced when opening a terminal (or loggin in tty) and source required files such as lib/functions.sh, lib/debug.sh to then call function to compute the prompt.

It also check if the user prompt required an upgrade if need.

The fact that this file mainly source other files is to ensure dynamicity of the development, as such, every modification done to other scripts are reload automatically as they are resourced each time.

Thus only modification done in this files requires to resource ~/.bashrc or /.zshrc.