Adding updates in frontend, and interface implementations in backend

astro/services/Competition.go

astro/services/Seeding.go

astro/services/Stage.go

frontend/bindings/changeme/astro/services/competition.ts

frontend/bindings/changeme/astro/services/models.ts

frontend/bindings/changeme/astro/services/pool.ts

frontend/src/App.svelte

frontend/src/common/NavBar.svelte

frontend/src/components/Seedings/Registrations.svelte

main.go