Enhance docs for New Contributors

[sharkAndshark]

• Check the installation of tools used in test.sh (jq file..). Originally suggested by @CommanderStorm
• Document How to work with just to test, to preview and build martin book, etc... in development.md (or maybe a new file)

[nyurik]

do we really want to have the starting script as a bash test.sh? I think some just recipes would be sufficient to do any kind of validation. We could even hack together a validation of just itself using {{just_executable()}} --version and to check if it is too old using semver_matches() just function:

{{semver_matches(shell(just_executable(), '--version'), ">1.38")}}

P.S. see also casey/just#2616

[sharkAndshark]

Just recipe better

[jjcfrancisco]

This is great guys. I'd be keen to contribute.