DatePosition - TCN API

where the date should be in position to the prefix, suffix and filename
for ConstructedFilename messages.
NOTE: Originally file defaulted to AFTER_FILENAME, this would change it to be
before the prefix
(-- api-linter: core::0126::unspecified=disabled
aip.dev/not-precedent: We need to keep the numbering the same since this existed before we started aip . --)

tcn.lms.element.v1alpha1.DatePosition(DatePosition)