Better ParaGridIO inputs without XIOS

[einola]

We should have the option of running a reasonably usable model without XIOS. So, we need some improvements to ParaGridIO:

1. Implement reading in of (mostly) un-preprocessed netCDF files for the ERA5 and TOPAZ forcing
2. Implement bilinear interpolation of those fields onto the model grid
3. Implement vector rotation for the vector fields (already an issue: Vector rotation in I/O operations #1087 - also applicable for XIOS)
4. Update the IParaGridIO interface so that the user can choose

• The original ParaGridIO interface (good for testing and idealised setups)
• The updated ParaGridIO interface (good for medium complexity setups)
• XIOS (for high-performance setups)

I will work on these issues in that order, merging each sub-PR into a base branch, which can then be merged into develop in its entirety, without a very thorough review (as this has already happened through the other PRs).