feat: implement appservices

Cargo.lock

Cargo.toml

src/appservice_server.rs

src/client_server/account.rs

src/client_server/alias.rs

src/client_server/media.rs

src/client_server/membership.rs

src/client_server/message.rs

src/client_server/profile.rs

src/client_server/redact.rs

src/client_server/room.rs

src/client_server/state.rs

src/client_server/to_device.rs

src/database.rs

src/database/admin.rs

src/database/appservice.rs

src/database/globals.rs

src/database/media.rs

src/database/rooms.rs

src/database/sending.rs