Add comprehensive documentation for template usage.

[bparth24]

• Provides detailed instructions for creating new Bedrock web modules, including repository setup, configuration steps, and development workflow.
• Includes package structure overview, feature descriptions, and coding standards requirements for consistent module development.

@dlongley cc: @mandyvenables @davidlehn

Note: I tried cleaning up a bit with the first draft and documenting the process. I'm sure I may have missed stuff. So, looking for feedback.

[davidlehn]

• This is changing the README to have instructions about using the template itself. I'm not sure that's what is desired here. Those instructions are useful and should be somewhere though. I think the common "template" flow is to create a new repo, tell system you want to use a template repo, then you go in and fix everything up with new names, info, code, etc. So the README itself should be a template for the future repo.
• We do have something similar in progress over here: Modernize bedrock-module-template-http#6
• This repo was copied from the pouch-edv one, and all the code and test remain. That all needs to be removed. Perhaps leaving a few template tests so it's easy to see the pattern to drop in code when the template is used.