Add objectives for Galerkin force error and spectral condensation

[f0uriest]

trafficstars

These would be good to have in the main code, both for testing and for users to try experimenting with. They just need to be cherry picked from the constrained branch. Ideally we can get those in first since they're fairly self contained before moving on to the rest of the constrained stuff.

[dpanici]

Separate the two objectives

[dpanici]

Beyond what is done in this PR, it would be good to have a DESCUR-like capability to fit a surface to a given set of R,phi,Z points while also attempting to minimize spectral width.