JOSS article

• Version of the JOSS article, https://doi.org/10.21105/joss.01463 .
• New function utils.grid2grid to move from one grid to another. Both functions (utils.get_receiver and utils.grid2grid) can be used for fields and model parameters (with or without extrapolation). They are very similar, the former taking coordinates (x, y, z) as new points, the latter one another TensorMesh instance.
• New jitted function njitted.volume_average for interpolation using the volume-average technique.
• New parameter conjugate in solver.solver to permit both Fourier transform conventions.
• Added exit_status and exit_message to info_dict.
• Add section Related ecosystem to documentation.