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>

HaikuDepot: Languages List

Abstacts the list of supported languages into
the LanguageModel class preventing use of
List. Also; fix a few cases where newer
logging techniques may have caused incorrect
logic flow.

Relates To #15534

Change-Id: I144fe4788abdaf0d93e53eeabc97b3f7aa2ec710
Reviewed-on: https://review.haiku-os.org/c/haiku/+/3085
Reviewed-by: Adrien Destugues <pulkomandy@gmail.com>

HaikuDepot: Better Logging

Changes the logging in HD to use a macro for the
various log levels to declutter the code and to
make it easier to more systematically log.

Change-Id: I025970707a0a11e7e3aaa4b52fc91288af0183f5
Reviewed-on: https://review.haiku-os.org/c/haiku/+/3018
Reviewed-by: Adrien Destugues <pulkomandy@gmail.com>

HaikuDepot: format string fixes.

HaikuDepot: Improve icon download handling performance

Previously each icon would launch an independent HTTP request to
pull down the HVIF icon data. This change means that the data
will be pulled down in bulk across all packages as a .tgz and
will then be kept in a cache locally. The client-server logic
will use standard "If-Modified-Since" headers to check for
updates each time the HaikuDepot desktop application starts up.
This arrangement will bring down the HVIF as well as bitmap
icons and use the best representation it can.

Additionally, it is possible from a command-line option to log
HTTP traffic verbosely and it is also possible to use an "-h"
flag to display help on command-line arguments.

The code-structure around this change also anticipates some
future extensions to handle other client-server improvements.

Fixes #11804