Support new `GALLEON_DIR` and `GALLEON_PROVISION_FEATURE_PACKS` when using S2I.

[jmesnil]

Is your feature request related to a problem? Please describe.

With https://issues.redhat.com/browse/CLOUD-3928, the user can specify a directory containing Galleon provisioning.xml as well as additional feature packs to provision when the application image is built.

To be consistent with the existing usage of galleonLayers, we will add 2 new fields to the build.s2i section.

Additional Galleon Feature packs

• featurePacks
  • type: string
  • required: false
  • description: a list of comma-separated GAVS of feature pack to install during provisioning (in addition to the server own feature-pack) or an array of GAVs
  • examples:

build:
  s2i:
    featurePacks: "org.example:foo-feature-pack:1.0,org.foo:my-other-feature-pack:5.0" `

or

build:
  s2i:
    featurePacks:
      - org.example:foo-feature-pack:1.0
      - org.foo:my-other-feature-pack:5.0

Custom Galleon Directory

• galleonDir
  • type: string
  • required: false
  • description: a path (relative to the application root directory) to a directory containing Galleon provisioning files (such as provisioning.xml)
  • example: "mysubdir/galleon"

Additional context

Implementation wise, in the BuildConfig for the build-artifacts:

• if the featurePacks is not empty, we use its value for the GALLEON_PROVISION_FEATUREPACKS environment variable.
• if the galleonDir is not empty, we use its value for the GALLEON_DIR environment variable.

[jmesnil]

Work to support these env vars in WildFly S2I images is described in https://github.com/wildfly/wildfly-proposals/pull/379 and done in https://github.com/wildfly/wildfly-s2i/pull/151 & https://github.com/wildfly/wildfly-s2i/pull/151