[Feature request]: support parameters with dimensions

[pearsonca]

Label

enhancement, gempyor

Priority Label

medium priority

Is your feature request related to a problem? Please describe.

Users identified multiple cases where parameters had to be generated by a configuration file to loop overall, for example, all strata and fill in a contact variable.

Is your feature request related to a new application, scenario round, pathogen? Please describe.

No response

Describe the solution you'd like

Should be able to specify something like:

parameter:
  cij: [[1, 0.5], [0.5, 1]]

when using with action validation / dry-run, should both check and explain stratifications.

Also desired: the ability to inflate this from a file, either in ij (i.e. value in positions row i x col j) or long (i.e. from j, to i, value) formats