Add installed plugins to the readme automatically

[nelsonamaya82]

Create a script that add the plugins names to the readme automatically after running composer install (which can be called in the "post-install-cmd" script) then we'll just need to add to the readme what they are used for.

[adamf321]

I would lean towards linting to check the list in the readme matches the list in composer.json, rather than automatically adding. The reason being that if the script automatically adds them then it's too easy to forgot to actually fill in the additional info which provides the value we're aiming for.