add apiv2 healthcheck code

reworking binding and endpoint to actually work.  added documentation in swagger for and various return code possibilities.  add a good start on tests though we need some other container functions not yet implemented for that.

Signed-off-by: Brent Baude <bbaude@redhat.com>

pkg/api/server/swagger.go

@@ -156,3 +156,12 @@ type swagVolumeListResponse struct {
 	// in:body
 	Body []libpod.Volume
 }
+
+// Healthcheck
+// swagger:response HealthcheckRun
+type swagHealthCheckRunResponse struct {
+	// in:body
+	Body struct {
+		libpod.HealthCheckResults
+	}
+}