[Feature]: add protection level to control rule options

[Rick-Methot-NOAA]

Describe the solution you would like.

A study for N Pacific stocks needs to implement the 20% SSL cut-off which overrides the normal control rule. This is like the overfished threshold for the west coast (the control rule between 0,2 and 0.25B0 is never used). I have therefore updated the forecast options to include a "protection level", which would be 20% B0 for Pacific cod and pollock etc. To avoid confusion with new options one only reads in a protection level if the lower limit of the normal HCR < 0 (H1020_bot <0 doesn't seem to be used) - obviously I correct the lower limit of the HCR as well so the code gives the same answers if there is no protection level. I used the join trick to avoid non-convergence.
Proposed code changes have been provided by Andre.

Describe alternatives you have considered

none obvious

Statistical validity, if applicable

OK here, this change is consistent with general development of control rules in SS3

Describe if this is needed for a management application

Perhaps. Only needed for a research study at this time

Additional context

No response