✨(frontend) introduce frontend Docker Image

To facilitate deployment on Kubernetes, we've introduced a Docker image for the
frontend. The Next.js project is built, and its static output is served using an
Nginx reverse proxy.

Since DevOps lacks a certified cold storage solution (e.g., S3) for serving
static files, we've decided to containerize the frontend as a quick workaround
for deploying staging environments.

Please note this Docker Image is WIP. One of the main issue still not resolved
concerns environment variables, which are only available when building the
Docker Image. Thus, having different environment variables values between
environment (dev, pre-prod, prod) will require us to build several frontend
images, and tag them with the appropriate target environment.

The `.env.production` values are not the final ones. For now, they were set to
dev values. It allows us to test the frontend image with the development setup.

Important: The frontend image is built-on top of an unprivileged Nginx image,
which exposes by default port 8080 instead of 80 for classic Nginx image.
You can find more info https://github.com/nginxinc/docker-nginx-unprivileged.

The Docker Compose Nginx service is used to proxy OIDC requests to keycloak,
in order to share the same host when initiating an OIDC flow, from outside and
inside docker virtual network.

All Nginx configurations related to serve frontend static build were moved to a
newly created conf file under src/frontend/apps/desk. When starting the frontend
image, we desire to start the minimum Nignx config required to serve frontend
statics.

docker/files/etc/nginx/conf.d/default.conf

@@ -1,37 +1,3 @@
-server {
-
-    listen 8082;
-    server_name localhost;
-    charset utf-8;
-
-    location /media {
-        alias /data/media;
-    }
-
-    location / {
-         proxy_pass http://app:8000;
-         proxy_set_header Host $host;
-         proxy_set_header X-Real-IP $remote_addr;
-         proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
-    }
-}
-
-server {
-  listen 8088;
-  server_name localhost;
- 
-  root /home/desk;
- 
-  location / {
-      try_files $uri index.html $uri/ =404;
-  }
- 
-  error_page 404 /404.html;
-  location = /404.html {
-      internal;
-  }
-}
-
 
 server {
     listen 8083;
@@ -45,4 +11,3 @@ server {
         proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
     }
 }
-