refactor: remove useless folders

.devcontainer.bk/Dockerfile

@@ -0,0 +1,8 @@
+FROM mcr.microsoft.com/vscode/devcontainers/rust:0-1
+
+RUN apt-get update && export DEBIAN_FRONTEND=noninteractive \
+     && apt-get -y install --no-install-recommends postgresql-client \
+     && cargo install sea-orm-cli cargo-insta \
+     && chown -R vscode /usr/local/cargo
+
+COPY .env /.env