Stateful configuration, context to process action

[TimothyWillard]

Modified the flepimop2 CLI to work with stateful configuration files
by adding a "history" top level key that tracks recent actions. This
allows for successive invocations of a configuration file to share
context. I.e. A user can simulate a model to produce some set of outputs
and then use the out configuration from said invocation to plot with the
process CLI that will have access to the recent simulation outputs.
Stateful configurations is optional, only used if the user explicitly
provides an output for the configuration.

• Added --out-config option to simulate/process that will dump the
  configuration file used to the given file for later reuse.
  Incorporated this feature into the external provider integration test.
• Added "history" top level key to the configuration model as a record
  of the actions performed with the configuration file. This is
  represented as a list of ActionModels which now replaces the
  previous RunMeta object.
• Configuration is now passed to ProcessABC.execute and supporting
  methods to provide context about recent invokations to the process
  action. Namely to connect a process action with recent simulate
  outputs.
• Renamed some variables within simulate/process CLIs for clarity.

Closes #55. Closes #62.

[pearsonca]

Minor stuff for this specifically, but bigger picture we should revisit the expected output of a flepimop invocation (e.g. i've argued it should be the resolved yaml file).

I also want to think a bit harder about the history element you're introducing here. I think we definitely need to do some kind of history-like-amendments to the config, but I'm torn as to whether its a top level thing vs a within-relevant-block item.

[pearsonca]

Thinking a bit about a simple shell invocation - what's a plausible standard way to pass the config information to a shell command invocation? I think approximately the path to the config file?

As in, let's imagine I want to define an arbitrary shell command, that's going to be executed in the working location that I call flepimop2. How would I run that command pointing to resolved location of the config file?