We need to make a new Markdown component.
react-native-markdown-renderer no longer meets all our need.

We need to accept:

• code
• link
• image
• at mention
• channelLink
• emoji
• hashtag
• paragraph
• heading
• code block
• block quote
• list
• item
• hardBreak
• thematicBreak
• softBreak
• htmlBlock
• htmlInline
• table
• table row
• table cell