Improve Remote Post

Problem

Remote post should be more flexible with fully integrated response confirmation

Solution

Refactor remote post to handle all submission states. Allow response to be inserted into submission data, emails, and confirmation pages via tokens

Steps

• Improve test coverage
• Write webform example remote post
• Restructure remote post to support all states
• Add webform-remote-post token support. Only supports current post.
• Add preprocess callback to WebformHandler
• Write confirmation code test
• Write confirmation page test