feature/inversion noise map

[Jammy2211]

The previous inversion API called the errors in a mesh source reconstruction as the property errors, which were defined as the variance in each mesh pixel.

This was confusing, as the errors were defined differently from the noise_map used throughout the code in dataset objects, and the errors required a np.sqrt to become the RMS standard deviation values like the noise_map.

This PR renames the inversion errors to the reconstruction_noise_map and includes the np.sqrt such that they are RMS standard deviations consistent with dataset objects.