Debugger: introduce ReadUInt

Change-Id: Iaa32db71b3a015d5496d60a96fb30763b924c89f
Reviewed-on: https://review.haiku-os.org/c/haiku/+/7103
Reviewed-by: Rene Gollent <rene@gollent.com>

Debugger: introduce target endianness handling

Change-Id: I597a667de1461383ce9e96e8ea9902895cf80ec6
Reviewed-on: https://review.haiku-os.org/c/haiku/+/7073
Tested-by: Commit checker robot <no-reply+buildbot@haiku-os.org>
Reviewed-by: Adrien Destugues <pulkomandy@pulkomandy.tk>

Debugger: implement ReadU24

Change-Id: I1385b935f229da51df959fd7644a9cd2d36e0e25
Reviewed-on: https://review.haiku-os.org/c/haiku/+/7058
Tested-by: Commit checker robot <no-reply+buildbot@haiku-os.org>
Reviewed-by: Jérôme Duval <jerome.duval@gmail.com>

Debugger: Split into core library and application.

- Add subfolder src/kits/debugger which contains the debugger's core
functionality and lower layers. Correspondingly add headers/private/debugger
for shared headers to be used by clients such as the Debugger application
and eventual remote_debug_server. Adjust various files to account for
differences as a result of the split and moves.
- Add libdebugger.so to minimal Jamfile.