Remove server-side infrastructure so developers can bring their own

[bgastelo]

https://www.pivotaltracker.com/story/show/188540638

This library contains phlex components and closely related JS/CSS.

• Remove "server-side infrastructure" (WS, rack, etc.)
• Refactor some components to expect inheritance for usage (instead of assuming usage of WS/rack server)
  • These Phlex components should provide more of an "Abstract" Chat interface, but the developer is expected to actually wire everything up in the back-end. I.e. Hook up the form, stream data to browser, etc.
  • Rename "Source" to "Modal::Reference"
  • Source a concept of our chatbot, whereas a Modal Link is something anyone could use.
• Add entrypoint "phlex/chatbot/rails" so that we can easily configure assets in a Rails environment.
  • This is entirely optional. If you use Sinatra or another framework, you can still use the Phlex components and CSS/JS.
• Rewrite some stimulus controllers to simplify their behavior

TODO:

• Refactor components to use inheritance and Phlex slots for customization
  • The Message should really just be an empty card and the slots header body footer
  • For Example, in our chatbot implementation we can add the "Copy" and "Regenerate" links
• Fix hotkeys for form submission (needs to also work w/ turbo if we are using it)
• Rename project to phlex-chat
• Add nice documentation and maybe link to example Rails repo