Pressure lost due to a saturated island

[logan-nc]

This PR adds a simple estimate of the pressure lost when an RMP driven island saturates to the saturated width predicted by Callen's model.

This can be used to compare to EPED to predict if an RMP island is expected to decrease the pedestal pressure enough to stabilize ELMs. It can also be benchmarked by comparing to TM1 results.

Example output when I boost the DIII-D ideal example to 1e6 amp I-coils:

...
Reading table from file: 
   g147131.02300_DIIID_KEFIT.kin
 Computing total resonant fields
           psi            q      singflx singlfx_crit     chirikov     w_island          w_v     w_v_crit        w_sat        w_min         dP/P
     5.936E-01        2.000    1.809E-01    4.729E-04        7.825    1.760E+00    3.008E-01    1.223E-01    1.261E-01    3.311E-03    2.378E-01
     8.186E-01        3.000    1.180E-01    2.396E-04       10.102    1.107E+00    2.285E-01    1.024E-01    1.028E-01    3.632E-03    2.761E-01
     9.282E-01        4.000    2.597E-02    5.624E-04        6.817    4.108E-01    1.766E-01    6.900E-02    9.333E-02    2.168E-03    1.068E+00
     9.884E-01        5.000    2.483E-01    9.979E-04       10.039    6.050E-01    1.112E-01    3.471E-02    8.126E-02    9.568E-04    8.048E+00
   split cpu time =            3  seconds
   total cpu time =           25  seconds
 Computing Clebsch displacements
...

In other words, that huge of an RMP would be expected to clobber the pedestal completely.
I like printing dP/P because it allows the user to eyeball if say ~10% of the pressure is eaten by an island at the pedestal top.
The netcdf saves both dP and P separately.

A known issue with the implementation is that each island is currently treated as perturbing the original pressure profile. When islands overlap, this is an over estimate. We should really work our way from the edge inwards and modify the pressure profile successively.

[logan-nc]

@priyanshlunia there is some bug in that last commit but it should be clear what I am trying to do. Can you fix it and plot the modified pressure profile from saturated islands? Post a screenshot when you do! TY