Improve Dockerfile layers caching
|Target version:||Release 2.7.0|
|Google Code Legacy ID:||Tested version:|
On the Docker Compose environment, rebuilding the AtoM services after any code change causes a full recreation of the containers. The Docker cache is not used due to the order of the layers in the Dockerfile, where the source code is copied to the containers on an initial step, causing the invalidation of the cache for the following layers.