Set default values for run time options

[gold2718]

• Add new metadata fields as discussed in the 2020-03-05 CCPP Framework Committee meeting.
• Make metadata for run-time options available through a ccpp_datafile report.

A major point to consider in the design is that many (if not most) of the run-time parameterization options are likely to be unknown to the host model. Therefore, in order to implement a solution, the host model build system will have to write some code to read in the user run-time settings and set the appropriate variables.

In order for the host cap to be created, a module will have to be created, adding the necessary variables to the host model so that the run-time variables can be passed to the suite.