🚀(helm) prepare staging deployment

Thx @rouja for your help on deploying Desk. This commit slightly modifies
helm charts and helmfile to prepare the initial project deployment in a
staging environment.

@rouja updates:
- added secrets files for dev and staging environments (dev's one is empty)
- disable ingress by default, to avoid any security issue
- added an extra chart to benefit from Indie hoster Postgres operator

Thx to this commit we deployed a first draft version figured out
that the Django session were broken. We are using a cache session engine,
and wrongly configure cache backend to local memory. Thus, Django server
is not able to resolve the session, and enters in an infinite loop to
log-in the user.

src/helm/env.d/dev/values.desk.yaml.gotmpl

@@ -0,0 +1,48 @@
+image:
+  repository: localhost:5001/people-backend
+  pullPolicy: Always
+  tag: "latest"
+
+backend:
+  envVars:
+    DJANGO_CORS_ALLOWED_ORIGINS: http://desk.127.0.0.1.nip.io,https://desk.127.0.0.1.nip.io
+    DJANGO_CONFIGURATION: Production
+    DJANGO_ALLOWED_HOSTS: "*"
+    DJANGO_SECRET_KEY: "ThisIsAnExampleKeyForDevPurposeOnly"
+    DJANGO_SETTINGS_MODULE: people.settings
+    DJANGO_SUPERUSER_PASSWORD: admin
+    DJANGO_EMAIL_HOST: "mailcatcher"
+    DJANGO_EMAIL_PORT: 1025
+    OIDC_OP_JWKS_ENDPOINT: https://fca.integ01.dev-agentconnect.fr/api/v2/jwks
+    OIDC_OP_AUTHORIZATION_ENDPOINT: https://fca.integ01.dev-agentconnect.fr/api/v2/authorize
+    OIDC_OP_TOKEN_ENDPOINT: https://fca.integ01.dev-agentconnect.fr/api/v2/token
+    OIDC_OP_USER_ENDPOINT: https://fca.integ01.dev-agentconnect.fr/api/v2/userinfo
+    OIDC_RP_CLIENT_ID: "ThisIsAnExampleIdForDevPurposeOnly"
+    OIDC_RP_CLIENT_SECRET: "ThisIsAnExampleKeyForDevPurposeOnly"
+    OIDC_RP_SIGN_ALGO: RS256
+    OIDC_RP_SCOPES: "openid email"
+    OIDC_REDIRECT_ALLOWED_HOSTS: https://desk.127.0.0.1.nip.io
+    OIDC_AUTH_REQUEST_EXTRA_PARAMS: "{'acr_values': 'eidas1'}"
+    LOGIN_REDIRECT_URL: https://desk.127.0.0.1.nip.io
+    LOGIN_REDIRECT_URL_FAILURE: https://desk.127.0.0.1.nip.io
+    LOGOUT_REDIRECT_URL: https://desk.127.0.0.1.nip.io/login
+    DB_HOST: postgres-postgresql
+    DB_NAME: people
+    DB_USER: dinum
+    DB_PASSWORD: pass
+    DB_PORT: 5432
+    POSTGRES_DB: people
+    POSTGRES_USER: dinum
+    POSTGRES_PASSWORD: pass
+
+frontend:
+  image:
+    repository: localhost:5001/people-frontend
+    pullPolicy: Always
+    tag: "latest"
+
+ingress:
+  enabled: true
+  host: desk.127.0.0.1.nip.io
+
+