Reset header stamps to zero in reset methods

[christophfroehlich]

Can't we leave it with zero time by default?

Originally posted by @saikishor in #1721 (comment)

Occurrences of these pattern, list maybe not exhaustive:

• https://github.com/ros-controls/ros2_controllers/pull/1721/files#r2164919633
• https://github.com/ros-controls/ros2_controllers/pull/1721/files#r2165976859
• https://github.com/ros-controls/ros2_controllers/pull/1721/files#r2164879546