Blanket suppression of warnings in `desc.plotting`

[unalmis]

trafficstars

We should not blanket suppress warnings in DESC, but we do this in desc.plotting when computing stuff. There are a few warnings that we would otherwise raise that the user needs to know about.

If there is a specific warning one would like to suppress, that should be done in a fine-grained manner by creating a custom warning class to filter here. A less robust option is to use the warnings library's pattern matching option.'

(We should also grep the source code and replace similar blanket warning suppression with fine grained filter).

[unalmis]

match for NFP basis warning

[dpanici]

Also for grid resolution, we should make sure the default plot grid for computing always has sufficient resolution for the given equilibrium/object