Show expanded buildrequires in API output
ModuleBuild.json now includes xmd/mbs/buildrequires in the output JSON
data. As a result, these APIs will show buildrequires by default.
* /module-builds/
* /module-builds/?verbose=True
* /module-builds/$build_id
Buildrequires is accessible like this:
br_module_names = response_json['buildrequires'].keys()
br_module_dict = response_json['buildrequires'][module name]
Fixes: FACTORY-2201
Signed-off-by: Chenxiong Qi <cqi@redhat.com>