Feat: add PPCG solver for PW diagonalization #16285

Job	Run time
Build without LCAO	4m 13s
Build with Intel toolchain	7m 35s
Build without ELPA	7m 56s
Build with CUDA support	13m 15s
Build with GNU toolchain	6m 7s
Build extra components with GNU toolchain	16m 27s
Build extra components with Intel toolchain	15m 28s
Build without MPI	6m 0s
Build without LCAO and MPI	4m 11s
	1h 21m 12s

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