Update for portuguese brazilian translation

Files edited

    config/locales/server.pt_BR.yml
    plugins/emoji/config/locales/server.pt_BR.yml
    plugins/poll/config/locales/client.pt_BR.yml
    plugins/poll/config/locales/server.pt_BR.yml
    public/403.pt_BR.html
    public/422.pt_BR.html
    public/500.pt_BR.html
    public/503.pt_BR.html
    vendor/gems/discourse_imgur/lib/discourse_imgur/locale/server.pt_BR.yml