Status posting

Waiting for design, but there's a lot that can already be done. Features needed:

• subject (cw) input field
• status input field
• media upload (no need to obey mastodon restrictions in number of attachments or types of attachments)
  • should have both file picker and drag-and-drop support
  • should show previews for uploaded files that can be previewed sensibly

polls, user and emoji suggestions can be done later