VF Chatbot : Angular support for chatbot components

@mshujamalik-ebi as discussed,  this ticket is to create Angular files for below chatbot components:

- vf-chatbot-action-prompt
- vf-chatbot-dialog
- vf-chatbot-fab
- vf-chatbot-feedback
- vf-chatbot-modal
- vf-chatbot-prompt
- vf-chatbot-selector
- vf-chatbot-sources
- vf-chatbot-standalone
- vf-chatbot-welcome
- vf-chatbot