Switch to gradle as the build tool

Signed-off-by: Ferry Huberts <ferry.huberts@pelagic.nl>
Install gradle in the workspace

Signed-off-by: Ferry Huberts <ferry.huberts@pelagic.nl>
findbugs: more effort and more reports

Signed-off-by: Ferry Huberts <ferry.huberts@pelagic.nl>
Fix bundle descriptions

Signed-off-by: Ferry Huberts <ferry.huberts@pelagic.nl>