selftests/bpf: add veristat replay mode

selftests/bpf: add veristat replay mode

Replay mode allow to parse previously stored CSV file with verification
results and present it in desired output (presumable human-readable
table, but CSV to CSV convertion is supported as well). While doing
that, it's possible to use veristat's sorting rules, specify subset of
columns, and filter by file and program name.

In subsequent patches veristat's filtering capabilities will just grow
making replay mode even more useful in practice for post-processing
results.

Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/r/20221103055304.2904589-2-andrii@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>