QUANTUM ESPRESSO implementation of the RPA-based functional

We detail our implementation of the random-phase-approximation based functional (RPAF) derived in Ref. [1] for the QUANTUM ESPRESSO (QE) package. We also make available in the Computer Physics Communications library the source files which are required in order to apply this functional within QE. We also provide the corresponding RPAF projector augmented wave (PAW) and ultrasoft pseudopotentials for most elements. Lastly, we benchmark the performance of the RPAF by calculating the equilibrium lattice constant and bulk modulus of a set of the same 60 crystals used by other authors to benchmark other functionals for both PAW and ultrasoft pseudopotentials. We find that the RPAF performs better overall as compared to the other most popular functionals.