Add keys for description, homepage, authors, issues and source in the composer.json

Problem/Motivation

Add keys for description, homepage, authors, issues and source in the composer.json. This recommendation from Drupal.org is helpful for users that run the command composer show drupal/webform_product to get more information, so it'll be displayed

Steps to reproduce

Proposed resolution

Just add these keys in the composer.json file

Remaining tasks

User interface changes

API changes

Data model changes