Lighten Strapi CMS: drop unused cloud plugin, disable telemetry/promo UI

Remove @strapi/plugin-cloud (deploy is self-hosted via Docker/Ansible,
never Strapi Cloud), disable the admin NPS/Enterprise-promotion flags
(single-admin panel, no upsell needed), disable Strapi's anonymous
telemetry, and prune dev dependencies from the production Docker image
layer.

cms/.env.example

@@ -6,3 +6,4 @@ ADMIN_JWT_SECRET=tobemodified
 TRANSFER_TOKEN_SALT=tobemodified
 JWT_SECRET=tobemodified
 ENCRYPTION_KEY=tobemodified
+STRAPI_TELEMETRY_DISABLED=true