This patch adds a new configuration setting to enable/disable jobboard
functionality in the amphorav2 provider. When disabled, the amphorav2
provider behaves similarly to the amphora v1 provider.
The default setting is jobboard disabled while jobboard remains an
experimental feature.
Change-Id: I063d832f5a049d7ae38378766200c7f82a35996d
bb9b30be7e