Generalizing `experiment` and `experiment2`

[eliotmcintire]

Both experiment and experiment2 need updating to accommodate many changes that have occurred in the LandR workflows, the McIntire et al 2022 Ecol Letters PERFICT paper, and changes in the various SpaDES packages. Here is a working list of these changes. We will have a meeting to discuss these in April 2022:

• Custom experimental setup (i.e., not only full factorial; e.g., LHS)
• Multi-machine workflows
• “Fitting” vs “simulation” workflows
• Store relevant metadata on simulation runs, output files, etc. (or facilitate extracting these from a ismLists object)
• Incorporate simstatus database + queue ?
• Incorporate upload/download queue ?