Maintenance: Reduce docker image build size by excluding node_modules folder

contrib/packager.io/after.sh

@@ -10,5 +10,5 @@ set -eux
 # delete asset cache
 rm -r tmp/cache
 
-# delete node_modules folder - only required for building
+# delete node_modules folder - only required during building
 rm -rf node_modules

script/build/cleanup.sh

@@ -29,3 +29,6 @@ rm -rf doc/developer_manual
 
 # Various development files
 rm -rf .dev
+
+# Delete node_modules folder - only required during building
+rm -rf node_modules