Added the implementation of BIKE Level-5

[dkostic]

Added the implementation of BIKE Level-5

The main changes are in the gf2x inversion where the k-squaring functions are modified to suport the Level-5 block size which is larger than 32768. The following files are changed: src/gf2x/gf2x_inv.c src/gf2x/gf2x_ksqr_avx2.c src/gf2x/gf2x_ksqr_avx512.c

The rest of the changes are the following:

• include/internal/bike_defs.h: added Level-5 parameters
• include/internal/defs.h: added macro required in gf2x
• include/internal/x86_64_intrinsic.h: added new macros for the intrinsics required in gf2x inversion for Level-5
• src/decode/decode.c: turned on support for Level-5
• tests/kats/BIKE_L5.kat: added Level-5 KAT
• tests/tests_kats.sh: added tests for Level-5
• tests/tests_sanitizers.sh: added tests for Level-5

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[drucker-nir]

Thanks Dusan for adding this, looks good.