Write a guide for working with Composer

[PriyaBhatia0210]

From the survey, there is feedback from some developers who say they find it difficult to understand how does a Composer works. We could perhaps add more documentation to explain this.

Acceptance criteria:

• Basic composer usage
• Best practices
• Troubleshooting

[roborourke]

Acquia have a good guide here https://support.acquia.com/hc/en-us/articles/360048081273-Using-Composer-to-manage-dependencies-in-Drupal-8-and-9

[rmccue]

This is only a could have and is quite stale, closing.

[roborourke]

Reopening as there are some hard to debug composer issues and it would be useful to have a specific guide to point people to when they run into problems.