gradle: Pass bnd gradle plugin classpath to build.gradle

Plugin coordinates are in gradle.properties and ivy repository is setup
in settings.gradle. We do that to use the plugin from the cloudbees
build.

Signed-off-by: BJ Hargrave <bj@bjhargrave.com>
Ensure cnf/cache/ folder is present upon git checkout

We adjust the .gitgnores by placing a .gitignore file in the cnf/cache/
folder. We need the folder always present, so we can locally cache the
cloudbees bundles for bnd.

Signed-off-by: BJ Hargrave <bj@bjhargrave.com>
Use ${build} instead of ${workspace}/cnf

Signed-off-by: BJ Hargrave <bj@bjhargrave.com>
Cache bnd repo in cnf/cache/

Caching in the default location of ~/.bnd/cache caused some build
failures because the bnd repo changes for each bnd build and that upset
the repo logic occasionally.

Signed-off-by: BJ Hargrave <bj@bjhargrave.com>
Use bnd_repourl in gradle.properties as the location of the bnd repo build

This allows the repo url to be externally set in the CI build with the
gradle command line option -Pbnd_repourl=<url>.

Signed-off-by: BJ Hargrave <bj@bjhargrave.com>
Set bnd_repourl gradle property into Workspace

This allows the repo url to be externally set in the CI build with the
gradle command line option -Pbnd_repourl=<url>.

Signed-off-by: BJ Hargrave <bj@bjhargrave.com>