refactor: Rename all remaining conduwuit references to Continuwuity

Also adds an alias for the old binary name to the dockerfile

Supersedes !1485
Closes #1536
Closes #2277

docs/public/deploying/docker-compose.with-caddy.yml

@@ -18,7 +18,7 @@ services:
   homeserver:
     image: "forgejo.ellis.link/continuwuation/continuwuity:latest"
     restart: unless-stopped
-    command: /sbin/conduwuit
+    command: /sbin/continuwuity
     volumes:
       - db:/var/lib/continuwuity
       - ./continuwuity-resolv.conf:/etc/resolv.conf # use custom resolvers rather than Docker's