Improve documentation

Problem/Motivation

I've recently started using AdvancedQueue in a site with a lot of different processing needs. It's a great module, but the documentation is so minimal as to make it very difficult to get started. The README.md is incredibly basic. This tutorial by Eric Pugh is a big help, but definitely doesn't cover the full features of the module.

Some open questions not answered in the existing documentation (just the README.md):

• What are the drush commands and their arguments?
• What are the factors that go into choices of different queue backends?
• How are retries configured? Do they go to the end of the queue on failure or stay at the front and are skipped until their minimum time-out?
• How does one bulk-create jobs?

Proposed resolution

Either enhance the breadth of documentation available in the README or add documentation pages on Drupal.org. Any documentation should be linked from the module homepage.

Remaining tasks

• Decide on a location for documentation
• Start improving the documentation
• Link to that documentation location from the project page.

User interface changes

none

API changes

none

Data model changes

none