convert Client into Service

src/admin/federation/commands.rs

src/api/client/media.rs

src/service/client/mod.rs

src/service/globals/mod.rs

src/service/mod.rs

src/service/pusher/mod.rs

src/service/sending/appservice.rs

src/service/sending/mod.rs

src/service/sending/resolve.rs

src/service/sending/sender.rs

src/service/service.rs

src/service/services.rs

src/service/updates/mod.rs