Refactor loading application-conf directory

zAppBuild is hard-coding how the application-conf directory is picked up:

https://github.com/IBM/dbb-zappbuild/blob/9beaa5847a20dae2a8a1cbffc44fe6652e081222/build.groovy#L363-L373

There are a couple of weaknesses with this code in this area:

It is not checked if the property file exist; this can lead to unpleasant messages like a FileNotFoundException.
repository layouts have to follow a pretty strict format to provide the application-conf directory, requiring workspace/application/application-conf.

The applicationConfRootDir property is overwriting the root directory path to the application, allows users today to modify the root path to application-conf.

Proposal is to provide more flexibility and externalise how the location of the application-conf directory is specified and let the engineering team define how it should look like. Even a hidden .zAppBuild directory could be a valid path in the application repository.

IBM / dbb-zappbuild

Refactor loading application-conf directory #399