[apparmor] [PATCH v3 0/2] apparmor: switch from zlib to zstd

[Jon Tourville]

This changes the algorithm used by apparmor to compress profile data
from zlib to zstd, using the new zstd API introduced in 5.16.

Zstd provides a larger range of compression levels than zlib and
significantly better performance at the default level (for a relatively
small increase in compressed size).

At the default compression levels, zstd's execution time was 16% that
of zlib with a size of 111%. At maximum compression levels, zstd's
execution time was 187% that of zlib with a size of 88%. This gives
users options for either improving performance or decreasing memory
usage over zlib.

Performance testing was done in the kernel against the default set of
profiles loaded by a fresh install of Ubuntu 22.04 desktop.

v3: Patch review changes
    - Removed unnecessary labels from apparmorfs min/max functions
v2: Patch review changes
    - Reallocate output buffer to the compressed size
    - Add sysfs files to expose min/max values for
      raw_data_compression_level