feat(rss): add soundbites according to the podcastindex specs

app/Config/Routes.php

app/Controllers/Admin/Episode.php

app/Database/Migrations/2020-06-05-180000_add_soundbites.php

app/Entities/Category.php

app/Entities/Episode.php

app/Entities/Soundbite.php

app/Entities/User.php

app/Helpers/rss_helper.php

app/Language/en/Breadcrumb.php

app/Language/en/Episode.php

app/Language/fr/Breadcrumb.php

app/Language/fr/Episode.php

app/Models/SoundbiteModel.php

app/Views/_assets/icons/bookmark.svg

app/Views/_assets/icons/play.svg

app/Views/_assets/icons/timer.svg

app/Views/_assets/modules/Charts.ts

app/Views/_assets/modules/Soundbites.ts

app/Views/_assets/soundbites.ts

app/Views/admin/_layout.php