Allow chat history to take React nodes with props, as well as Conversation[] or { [key: string]: Conversation[]}

[rebeccaalpert]

We want to be able to enable products to easily add things on their own without waiting for us, like:

• lock icons
• additional actions you can take on each item
• tooltips
• things like favoriting

We want this to be non-breaking for products already using existing Conversation API.

[rebeccaalpert]

Spoke to Nicole about how much we want to break this open:

• Nicole wants to go back to Menu implementation so we can pick up favorites (reevaluate list approach if and when it becomes an issue again)
• Make sure we are passing props down in object for everything so products can do whatever they so desire