[ci skip] Move Terraform modules into stack directories

Move all 88 service modules (66 individual + 22 platform) from
modules/kubernetes/<service>/ into their corresponding stack directories:

- Service stacks: stacks/<service>/module/
- Platform stack: stacks/platform/modules/<service>/

This collocates module source code with its Terragrunt definition.
Only shared utility modules remain in modules/kubernetes/:
ingress_factory, setup_tls_secret, dockerhub_secret, oauth-proxy.

All cross-references to shared modules updated to use correct
relative paths. Verified with terragrunt run --all -- plan:
0 adds, 0 destroys across all 68 stacks.

stacks/platform/modules/monitoring/Dockerfile

@@ -0,0 +1,27 @@
+# dockerhub: viktorbarzin/redfish-exporter
+# repo: https://pkg.go.dev/github.com/jenningsloy318/redfish_exporter#section-readme
+FROM golang:rc-bullseye AS builder
+
+LABEL maintainer="Viktor Barzin <me@viktorbarzin.me>"
+
+ARG ARCH=amd64
+
+ENV GOROOT /usr/local/go
+ENV GOPATH /go
+ENV PATH "$GOROOT/bin:$GOPATH/bin:$PATH"
+ENV GO_VERSION 1.15.2
+ENV GO111MODULE=on 
+
+
+# Build dependencies
+RUN mkdir -p /go/src/github.com/ && \
+    git clone https://github.com/jenningsloy318/redfish_exporter /go/src/github.com/jenningsloy318/redfish_exporter && \
+    cd /go/src/github.com/jenningsloy318/redfish_exporter && \
+    make build
+
+FROM golang:rc-bullseye
+
+COPY --from=builder /go/src/github.com/jenningsloy318/redfish_exporter/build/redfish_exporter /usr/local/bin/redfish_exporter
+RUN mkdir /etc/prometheus
+# config file mounter at runtime
+CMD ["/usr/local/bin/redfish_exporter", "--config.file", "/etc/prometheus/redfish_exporter.yml"]