chore: Remove yarn docker-build:app command and related docs

contrib/docker/frontend-with-nginx/Dockerfile

@@ -8,8 +8,6 @@ FROM nginx:mainline
 # This dockerfile requires the app to be built on the host first, as it
 # simply copies in the build output into the image.
 
-# The safest way to build this image is to use `yarn docker-build:app`
-
 RUN apt-get update && apt-get -y install jq && rm -rf /var/lib/apt/lists/*
 
 COPY packages/app/dist /usr/share/nginx/html

docs/overview/architecture-overview.md

@@ -185,17 +185,6 @@ separate Docker images.
 
 ![Boxes around the architecture to indicate how it is containerised](../assets/architecture-overview/containerised.png)
 
-The frontend container can be built with a provided command.
-
-```bash
-yarn install
-yarn tsc
-yarn run docker-build:app
-```
-
-Running this will simply generate a Docker container containing the contents of
-the UIs `dist` directory.
-
 The backend container can be built by running the following command:
 
 ```bash

package.json

@@ -20,7 +20,6 @@
     "lint:all": "lerna run lint --",
     "lint:type-deps": "node scripts/check-type-dependencies.js",
     "docgen": "lerna run docgen",
-    "docker-build:app": "yarn workspace example-app build && docker build . -t spotify/backstage",
     "docker-build": "yarn tsc && yarn workspace example-backend build-image",
     "create-plugin": "backstage-cli create-plugin --scope backstage --no-private",
     "remove-plugin": "backstage-cli remove-plugin",