Remove Twitter stuff

assets/css/app.css

assets/js/dashboard/date.js

assets/js/dashboard/stats/devices/index.js

assets/js/dashboard/stats/locations/index.js

assets/js/dashboard/stats/modals/referrer-drilldown.js

assets/js/dashboard/stats/pages/index.js

config/runtime.exs

lib/plausible/stats/clickhouse.ex

lib/plausible/twitter/api.ex

lib/plausible/twitter/tweet.ex

lib/workers/fetch_tweets.ex

priv/repo/migrations/20211202094732_remove_tweets.exs

test/support/factory.ex

test/workers/fetch_tweets_test.exs