Move docker files in subdir

backend/Dockerfile

@@ -2,13 +2,16 @@ FROM node:12-buster-slim AS builder
 
 WORKDIR /build
 COPY . .
+
 RUN sed -i "s!../.git/refs/heads/master!master!g" ./src/api/backend-info.ts
+
 RUN apt-get update
 RUN apt-get install -y build-essential python3 pkg-config
 RUN npm ci --production
 RUN npm i typescript
 RUN npm run build
-RUN mv mempool-config-docker.json mempool-config.json
+
+RUN mv ./docker/* .
 
 FROM node:12-buster-slim