Adding POST /api/v1/reports API, and a UI for submitting reports

app/assets/javascripts/components/actions/compose.jsx

app/assets/javascripts/components/actions/reports.jsx

...s/javascripts/components/components/status_action_bar.jsx

app/assets/javascripts/components/containers/mastodon.jsx

...ts/javascripts/components/containers/status_container.jsx

...pts/components/features/account/components/action_bar.jsx

...omponents/features/account_timeline/components/header.jsx

...features/account_timeline/containers/header_container.jsx

...omponents/features/report/components/status_check_box.jsx

...features/report/containers/status_check_box_container.jsx

app/assets/javascripts/components/features/report/index.jsx

...ipts/components/features/status/components/action_bar.jsx

app/assets/javascripts/components/features/status/index.jsx

app/assets/javascripts/components/reducers/index.jsx

app/assets/javascripts/components/reducers/reports.jsx

app/assets/stylesheets/components.scss

app/assets/stylesheets/forms.scss

app/controllers/api/v1/reports_controller.rb

app/models/report.rb

app/views/api/v1/reports/index.rabl