Handle curvilinear or generic grids

[PBrockmann]

Some grid examples are available from:
https://vesg.ipsl.upmc.fr/thredds/catalog/IPSLFS/brocksce/gridsCF/catalog.html

See: sampleCurveGrid4.nc and sampleGenGrid3.nc

A DYNAMICO also available from: etopo05_dynamico_62412.nc

[WesleyTheGeolien]

At the moment the tools in the flask développement branch are aimed at the workflow of creating boundary conditions. This means that it expects the first file that is uploaded to be a Lon / Lat file and not a curvilinear grid.

I see 2 options here:

1. Pull out the useful code to make a more generic app and have the workflow pull certain of these tools in
2. Be able to upload a file and assign it a "step" which means you can carry on setting up the initial conditions even if you didn't start inside the app