PackageKit: add Zstd compression

[korli]

Zstd isn't available on x86_gcc2, so it might only be interesting for non-gcc2 archs.

see ​https://facebook.github.io/zstd/ for more information.

Adding another compression might require a package format version increment.

[korli]

Next step is obviously adding the compilation of zstd in the kernel in ​src/system/kernel/lib/zstd/Jamfile

packagefs and btrfs would use it, as with zlib (​src/add-ons/kernel/file_systems/btrfs/Jamfile, ​src/add-ons/kernel/file_systems/packagefs/Jamfile)

Packagefs shares most code with the userland package kit.

BtrFS has a zstd compression feature (to be implemented, BTRFS_EXTENT_COMPRESS_LZO 3).

[korli]

Draft patch to add Zstd as Hpkg compression format

[korli]

I updated the patch with the kernel lib and the packagefs changes.

Next step would be the bootloader, only useful for the haiku package. This can probably wait.

[apl-haiku]

Because HaikuDepotServer reads the HPKR format (repository catalog) which is a derivative of the HPKG format, can you please let me know ahead of time if you plan to use this compression for the chunks of the HPKR as I will have to get the server-side adapted to cope with this.

[korli]

Added support in libbe.so, the kernel lib, and extension of compress_test in hrev51615.

[pulkomandy]

The patch does not apply anymore. Is there anything in there that needs to be recovered, or are all the changes already integrated?

[pulkomandy]

Remaining changes migrated to Gerrit: ​https://review.haiku-os.org/#/c/haiku/+/323/

[waddlesplash]

Merged in hrev52209.

At what point should we switch Zstd compression to be default?