HaikuDepot: Remove Custom List

Further removal of the use of custom list class;
this time with the package lists.

Relates To #15534
Change-Id: I1f01ed9d5ddbd7754097ce0adbf505d6ba17fd2f
Reviewed-on: https://review.haiku-os.org/c/haiku/+/3732
Reviewed-by: Adrien Destugues <pulkomandy@gmail.com>

HaikuDepot: LRU Cache for Icons

Only keep a fixed number of icons in memory at once.

Completes To #15370

Change-Id: I23e3a4fa7559894034f45afb3b536910ea037078
Reviewed-on: https://review.haiku-os.org/c/haiku/+/3367
Reviewed-by: Rene Gollent <rene@gollent.com>

HaikuDepot: Icon / Tarball Handling

Instead of exploding the tar-ball of icons from
HDS, keep it as a tar-ball, index it and read
data directly out from specific indicies on demand.

This will speed up the process of downloading
the icons by removing the unpack. Also updates
will be faster by avoiding the need to delete the
old icon files.

Because icons are loaded on-demand, the start
time is faster by avoiding all the icon loads.
There are also savings on memory consumption.

Indexing on each load is surprisingly fast so
no external index is maintained. Likewise for
the tar-balls's meta-data.

This commit does not cover the implementation
of an LRU cache of the icons in memory.

Relates to #15370

Change-Id: Ia1647d8c805be89618f493d2592bf7877fca3f14
Reviewed-on: https://review.haiku-os.org/c/haiku/+/3205
Reviewed-by: Adrien Destugues <pulkomandy@gmail.com>