Remove unused release scripts and documentation

This has now being superceeded by the GitHub actions workflows so can be removed.

Author: NickColley

bin/build-release.sh

@@ -18,8 +18,6 @@
     "postinstall": "npm ls --depth=0",
     "start": "npm run dev",
     "generate-npm-tag": "./bin/generate-npm-tag.sh",
-    "build-release": "./bin/build-release.sh",
-    "publish-prerelease": "./bin/publish-prerelease.sh",
     "publish-preview": "./bin/publish-preview.sh",
     "predev": "npm run build -- --ignore-scripts",
     "dev": "concurrently \"npm run dev --workspace @govuk-frontend/review\" \"npm run dev --workspace govuk-frontend\" --kill-others --names \"app,pkg\" --prefix-colors \"red.dim,blue.dim\"",