chore: remove unused devcontainer and gitpod configs (#5029)

Author: yusukebe

.devcontainer/Dockerfile

@@ -56,7 +56,5 @@ If you want to do it, create an issue about your middleware.
 ## Local Development
 
 ```bash
-git clone git@github.com:honojs/hono.git && cd hono/.devcontainer && bun install --frozen-lockfile
-docker compose up -d --build
-docker compose exec hono bash
+git clone git@github.com:honojs/hono.git && cd hono && bun install --frozen-lockfile
 ```