Impossible to run large system (more than 200 orbitals) - FCIDUMP has to go

[anbenali]

It is impossible to generate an fcidump for a large system due to the crazy size of fcidump. We need the 3idx implementation of the integral stored in HDF5.

In short, we only need to read the hdf5 file (already generated from qp2). This is the only way to test the code for large(r) systems.

[TApplencourt]

Agree!

Yeah, was planing to use the new thing from Anthony. Sound like a nice generalize fcidump. Don't remember the name. But don't have the energy to reimplementing everything in Python if we are porting to C++ later. But maybe using qp2 hdf5 to start can be easy enough.
PR are welcome :)