Publish static transforms on /tf but not on /tf_static.
 - see the code comments why.
header's stamp - from :reader to :accessor

stamped-transform's - header from :reader to :accessor

 - we want the stamp of the stamped-transform to be mutable
update-stamped-transform-stamp ()

 - we want to update on demand the stamp of a stamped-transform.
update-stamped-transform-stamp ()
 - returns the stamped transform having the newly set stamp