Create StatisticsReporter in Stochastic Tools

[aeslaughter]

Reason

The Statistics VPP in stochastic_tools can compute various quantities including confidence intervals. However, recording the calculations in CSV format is limiting and requires numeric codes to indicate what the vectors represent. Thus, to understand the output the input file is required.

The Reporter system allows for more generic types and JSON output, thus adds the ability to organize the calculations and compute more complex data types.

The generic, input file agnostic output is required for use with a digital twin project that requires JSON files to process with machine learning.

Design

Convert current capability of Statistics to a StatisticsReporter and support all the current calculations.

Impact

Statistics VPP will be deprecated.

[aeslaughter]

@jerenmb This is work for the LDRD. All my changes to MOOSE for the LDRD will be added to the project here: https://github.com/idaholab/moose/projects/16