[commands] Move GroupedCommands to CommandScheduler (#4728)

Move the command group checking functionality from CommandGroupBase into CommandScheduler.
Update references to grouping as composition for clarity (because explicitly grouping isn't the only way to do it).
Deprecate the static factory methods parallel, race, and deadline in CommandGroupBase in favor of the identical ones in Commands.

wpilibNewCommands/src/main/native/include/frc2/command/CommandScheduler.h

@@ -360,6 +360,34 @@ class CommandScheduler final : public nt::NTSendable,
    */
   void OnCommandFinish(Action action);
 
+  /**
+   * Requires that the specified command hasn't been already added to a
+   * composition.
+   *
+   * @param command The command to check
+   * @throws if the given commands have already been composed.
+   */
+  void RequireUngrouped(const Command* command);
+
+  /**
+   * Requires that the specified commands not have been already added to a
+   * composition.
+   *
+   * @param commands The commands to check
+   * @throws if the given commands have already been composed.
+   */
+  void RequireUngrouped(std::span<const std::unique_ptr<Command>> commands);
+
+  /**
+   * Requires that the specified commands not have been already added to a
+   * composition.
+   *
+   * @param commands The commands to check
+   * @throws IllegalArgumentException if the given commands have already been
+   * composed.
+   */
+  void RequireUngrouped(std::initializer_list<const Command*> commands);
+
   void InitSendable(nt::NTSendableBuilder& builder) override;
 
  private: