Adds Speakers DB table, :new endpoint, UI updates

[mdarby]

curl --request POST \
  --url http://localhost:4000/api/speakers \
  --header 'content-type: application/json' \
  --data '{
    "speaker": {
        "url": "url",
        "name": "name",
        "title": "title",
        "email": "matt@matchedpattern.com"
    }
}'