Remove obsolete docker-compose files

Since we moved to a monorepo, we have it in the top level folder.

backend/docker-compose.prod.yml

@@ -1,9 +0,0 @@
-version: "3.7"
-
-services:
-  neo4j:
-    environment:
-      - NEO4J_PASSWORD=letmein
-  backend:
-    environment:
-      - NEO4J_PASSWORD=letmein

webapp/docker-compose.override.yml

@@ -1,16 +0,0 @@
-version: '3.7'
-
-services:
-  webapp:
-    build:
-      context: .
-      target: build-and-test
-    volumes:
-      - .:/nitro-web
-      - node_modules:/nitro-web/node_modules
-      - nuxt:/nitro-web/.nuxt
-    command: yarn run dev
-
-volumes:
-  node_modules:
-  nuxt:

webapp/docker-compose.travis.yml

@@ -1,10 +0,0 @@
-version: "3.7"
-
-services:
-  webapp:
-    build:
-      context: .
-      target: build-and-test
-    environment:
-      - GRAPHQL_URI=http://backend:4123
-      - NODE_ENV=test

webapp/docker-compose.yml

@@ -1,23 +0,0 @@
-version: '3.7'
-
-services:
-  webapp:
-    image: humanconnection/nitro-web:latest
-    build:
-      context: .
-      target: production
-    ports:
-      - 3000:3000
-    networks:
-      - hc-network
-    environment:
-      - HOST=0.0.0.0
-      - GRAPHQL_URI=http://backend:4000
-      - MAPBOX_TOKEN="pk.eyJ1IjoiaHVtYW4tY29ubmVjdGlvbiIsImEiOiJjajl0cnBubGoweTVlM3VwZ2lzNTNud3ZtIn0.bZ8KK9l70omjXbEkkbHGsQ"
-
-networks:
-  hc-network:
-    name: hc-network
-
-volumes:
-  node_modules: