Service mission prep: add methods to Analyze2D to estimate resolving power

[awhoward]

They should generate 2D and 1D plots of resolving power across the spectral format based on LFC lines. This is needed before the February service mission.

@shalverson -- did you just fit a Gaussian and use the FWHM for $\Delta\lambda$ in $R = \lambda / \Delta\lambda$.

[shalverson]

I fit an error function, but yes. My steps were fit peaks in pixel space -> derive wavelength solution from fitted centers -> compute lambda / d_lambda for all peaks.