Add rpointer timestamp

[jedwards4b]

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Description of changes

This PR adds timestamps to the rpointer file names. It is done in a backward compatible manor so that the current rpointer files naming scheme will still work.

Specific notes

Contributors other than yourself, if any:

CDEPS Issues Fixed (include github issue #):

Are there dependencies on other component PRs (if so list): This depends on https://github.com/ESCOMP/CESM_share/pull/53

Are changes expected to change answers (bfb, different to roundoff, more substantial): bfb

Any User Interface Changes (namelist or namelist defaults changes):

Testing performed (e.g. aux_cdeps, CESM prealpha, etc): aux_cdeps, all pass

Hashes used for testing:

[mvertens]

@jedwards4b - I think that a few tests with active components would be important to do as well before this PR is merged. I would suggest 3 tests - F, I and G compsets.

[jedwards4b]

Thank you @mvertens I am completeing a full set of cesm3 prealpha tests.

[jedwards4b]

@mvertens I have completed prealpha and prebeta tests using cesm3_0_beta03 as a baseline.