Rename the typing server to EDU server (#948)

* Blunt move and sed rename

* Rename common/ refs to typing

* Rename internal stuff in eduserver

* Rename docs and scripts

* Rename constants/filenames, goimports everything to re-order imports

docker/docker-compose.yml

@@ -103,10 +103,10 @@ services:
     networks:
       - internal
 
-  typing_server:
-    container_name: dendrite_typing_server
-    hostname: typing_server
-    entrypoint: ["bash", "./docker/services/typing-server.sh"]
+  edu_server:
+    container_name: dendrite_edu_server
+    hostname: edu_server
+    entrypoint: ["bash", "./docker/services/edu-server.sh"]
     build: ./
     volumes:
       - ..:/build