Sprinkle bits of javadoc on the classes.

Signed-off-by: Lukas Krejci <lkrejci@redhat.com>

wsmaster/che-core-api-metrics/src/main/java/org/eclipse/che/api/metrics/WorkspaceActivityMeterBinder.java

@@ -20,6 +20,7 @@ import org.eclipse.che.api.core.ServerException;
 import org.eclipse.che.api.core.model.workspace.WorkspaceStatus;
 import org.eclipse.che.api.workspace.activity.WorkspaceActivityManager;
 
+/** Provides metrics of workspace activity. */
 @Singleton
 public class WorkspaceActivityMeterBinder implements MeterBinder {
 

wsmaster/che-core-api-metrics/src/main/java/org/eclipse/che/api/metrics/WsMasterMetricsModule.java

@@ -15,6 +15,10 @@ import com.google.inject.AbstractModule;
 import com.google.inject.multibindings.Multibinder;
 import io.micrometer.core.instrument.binder.MeterBinder;
 
+/**
+ * A Guice module to bind all our metric binders to a single multi-binder. The set of all metric
+ * binders is used to produce the Prometheus metrics on request.
+ */
 public class WsMasterMetricsModule extends AbstractModule {
 
   @Override