Early Stopping for Coupled Driver

[sean-engelstad]

• change preconditioner_steps to uncoupled_steps (never should have been coupled preconditioner_steps as that is a misnomer => we just hadn't changed it yet)
• add early stopping criterion to funtofem_nlbgs_driver (coupled driver)
• min_steps argument defaults to uncoupled_steps
• convergence tolerances added to discipline scenarios esp. FUN3D interface
• Could also add it to the TACS interface later (but we don't really use that for the early stopping criterion as the linear solve converges like 99.9% of the time)
• Early stopping will not work for the unsteady scenarios as the adjoints don't work for certain solvers (FUN3D) if the analysis exits early (also it doesn't really make sense to stop early in an unsteady scenario)
• NOTE: still need to test this out so marking as draft until it is tested
• Also note => my master branch has commits that didn't get discarded but they are equivalent to old commits so don't change the code. Please disregard these.

[sean-engelstad]

Not able to test this at the moment, the only thing left is to run jobs with it and prove that it works after correcting some code inside FUN3D.

[sean-engelstad]

Included in PR #249