refactor: move more show store logic into pinia store

src/Pages/AddOrEditPlaylist.vue

src/Pages/EmissionManager.vue

src/Pages/FileManager.vue

src/components/CalendarDayView.vue

src/components/nav/ANavSidebar.vue

src/components/nav/nav.ts

src/components/shows/AddShowModal.vue

src/components/shows/ShowSelector.vue

src/main.js

src/store/modules/shows.js

src/stores/auth.ts

src/stores/shows.ts

src/util.ts