Added .env.example files to all folders and changed the port env var for Gitea to follow naming convention

Gitea/docker-compose.yaml

@@ -13,7 +13,7 @@ services:
       - /etc/timezone:/etc/timezone:ro
       - /etc/localtime:/etc/localtime:ro
     ports:
-      - ${HOST_PORT}:3000
+      - ${GITEA_PORT}:3000
       - ${SSH_PORT}:2222
     depends_on:
       - db