Separate out package.json copy from the rest of the project
Separate out package.json copy from the rest of the project

By copying the package*.json files to the image then running npm install
will add a new layer to the image which can speed up the image build
time if the package.json file hasn't changed but the app files have.
This will allow the npm install step to be skipped

MOM-544

jembi/openhim-mediator-file-queue,jembi/openhim-mediator-file-queue