refactor: move dockerfiles to package folders

scheduled_tasks/Dockerfile

@@ -0,0 +1,15 @@
+FROM alpine:latest AS builder
+
+RUN apk add go
+
+WORKDIR /build
+
+COPY scheduled_tasks/ /build
+
+RUN go build .
+
+FROM alpine:latest
+
+COPY --from=builder /build/scheduled_tasks /bin/runner
+
+ENTRYPOINT ["/bin/runner"]