Add helper classes for managing aux data

[sethrj]

For #1746 .

[codecov[bot]]

Codecov Report

:x: Patch coverage is 90.90909% with 1 line in your changes missing coverage. Please review. :white_check_mark: Project coverage is 84.88%. Comparing base (f80a0ce) to head (2b03d3d). :warning: Report is 2 commits behind head on develop.

Files with missing lines	Patch %	Lines
src/celeritas/track/StatusChecker.cc	75.00%	1 Missing :warning:

Additional details and impacted files

@@             Coverage Diff             @@
##           develop    #2120      +/-   ##
===========================================
+ Coverage    84.86%   84.88%   +0.01%     
===========================================
  Files         1253     1254       +1     
  Lines        44141    44135       -6     
  Branches     16495    16492       -3     
===========================================
+ Hits         37460    37462       +2     
+ Misses        4713     4712       -1     
+ Partials      1968     1961       -7     

Files with missing lines	Coverage Δ
src/celeritas/global/CoreState.hh	69.23% <100.00%> (ø)
src/celeritas/track/StatusChecker.hh	80.00% <ø> (ø)
src/celeritas/user/detail/StepParams.cc	100.00% <ø> (ø)
src/celeritas/user/detail/StepParams.hh	87.50% <ø> (ø)
src/corecel/data/AuxInterface.hh	100.00% <ø> (ø)
src/corecel/data/AuxParams.hh	100.00% <100.00%> (ø)
src/corecel/data/AuxState.hh	68.00% <100.00%> (ø)
src/corecel/data/AuxStateVec.hh	85.00% <ø> (-1.37%)	:arrow_down:
src/corecel/data/Collection.hh	93.75% <ø> (ø)
src/corecel/data/CollectionMirror.hh	71.42% <ø> (ø)
... and 5 more

... and 8 files with indirect coverage changes

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[github-actions[bot]]

Test summary

 5 702 files   9 168 suites   17m 54s :stopwatch:  2 080 tests  2 054 :white_check_mark:  26 :zzz: 0 :x: 31 837 runs  31 689 :white_check_mark: 148 :zzz: 0 :x:

Results for commit 2b03d3d5.

:recycle: This comment has been updated with latest results.

[sethrj]

@amandalund Would you be able to give me any feedback on this and hit merge if you think it's ok?

[amandalund]

Will do!

[sethrj]

Thanks @amandalund , I've also removed the Data part of the class names from the params/state template classes, since we should be more consistent about using Data exclusively for collection groups.