Feature #2786 rpss_from_prob

Expected Differences

[x] Do these changes introduce new tools, command line arguments, or configuration file options? [No]
If yes, please describe:
No new inputs, but this adds support for is_prob = TRUE in the Ensemble-Stat fcst dictionary.
[x] Do these changes modify the structure of existing or add new output data types (e.g. statistic line types or NetCDF variables)? [No]
If yes, please describe:

[x] Describe testing already performed for these changes:
Added a new unit test in unit_ensemble_stat.xml and ran manually with a variety of inputs to test. Confirmed that hard-coding using the values from this slide do produce the expected results.
[x] Recommend testing for the reviewer(s) to perform, including the location of input datasets, and any additional instructions:
Test the code compiled in seneca:/d1/projects/MET/MET_pull_requests/met-12.0.0/beta4/MET-feature_2786_RPSS_from_prob.
[x] Do these changes include sufficient documentation updates, ensuring that no errors or warnings exist in the build of the documentation? [No] Not yet. Please add the documentation we discussed to the Ensemble-Stat and Appendix C chapters.
[x] Do these changes include sufficient testing updates? [Yes]
[x] Will this PR result in changes to the MET test suite? [Yes or No]
If yes, describe the new output and/or changes to the existing output:
Adds 1 new output .stat file from Ensemble-Stat:
```
ensemble_stat/ensemble_stat_RPS_CLIMO_BIN_PROB_20210101_000000V.stat
```
[x] Will this PR result in changes to existing METplus Use Cases? [No]
If yes, create a new Update Truth METplus issue to describe them. It should not.
[x] Do these changes introduce new SonarQube findings? [Yes or No]
If yes, please describe: Scan is running now: https://github.com/dtcenter/MET/actions/runs/8713559705?pr=2861
[x] Please complete this pull request review by [Wed 4/17].

See the METplus Workflow for details.

[ ] Review the source issue metadata (required labels, projects, and milestone).
[ ] Complete the PR definition above.
[ ] Ensure the PR title matches the feature or bugfix branch name.
[ ] Define the PR metadata, as permissions allow. Select: Reviewer(s) and Development issue Select: Milestone as the version that will include these changes Select: Coordinated METplus-X.Y Support project for bugfix releases or MET-X.Y.Z Development project for official releases
[ ] After submitting the PR, select the :gear: icon in the Development section of the right hand sidebar. Search for the issue that this PR will close and select it, if it is not already selected.
[ ] After the PR is approved, merge your changes. If permissions do not allow this, request that the reviewer do the merge.
[ ] Close the linked issue and delete your feature or bugfix branch from GitHub.