debian: stx-metrics-server-sample-app: port to debian

Since stx-metrics-server-sample-app doesn't inherit from the base
image, the Dockerfile didn't need to be changed, but to follow the
structure that was used in other apps that were migrated to debian,
some directories were changed.

Test Plan:
PASS: Debian - Build Debian docker image and upload/apply
metrics-server and metrics-server-sample-app. Verified that the app is
applied and the container is created.

PASS: CentOS - Same tests that were done on Debian.

Story: 2009831
Task: 44511

Signed-off-by: Luiz Felipe Kina <LuizFelipe.EiskeKina@windriver.com>
Change-Id: Ib59770209b9284e4463369234a6d833bd23232b2

debian_stable_docker_images.inc

@@ -0,0 +1,2 @@
+sample-app
+

sample-app/centos/sample-app.stable_docker_image

@@ -1,2 +1,4 @@
 BUILDER=docker
-LABEL=stx-metrics-server-sample-app
+LABEL=stx-metrics-server-sample-app
+DOCKER_CONTEXT=../docker/
+DOCKER_FILE=../docker/Dockerfile.centos

sample-app/debian/sample-app.stable_docker_image

@@ -0,0 +1,4 @@
+BUILDER=docker
+LABEL=stx-metrics-server-sample-app
+DOCKER_CONTEXT=../docker/
+DOCKER_FILE=../docker/Dockerfile.debian

sample-app/docker/Dockerfile.debian

@@ -0,0 +1,11 @@
+FROM node:14.15.5-alpine3.13
+
+WORKDIR /usr/src/app
+
+COPY src/package*.json ./
+
+RUN npm install
+
+COPY src/ .
+
+CMD [ "node", "sample-application.js" ]