samples/landlock: Add quiet flag support to sandboxer

samples/landlock: Add quiet flag support to sandboxer

Adds ability to set which access bits to quiet via LL_*_QUIET_ACCESS
(FS, NET or SCOPED), and attach quiet flags to individual objects via
LL_*_QUIET for FS and NET.

Assisted-by: GitHub-Copilot:claude-opus-4.8 copilot-reviepickw
Signed-off-by: Tingmao Wang <m@maowtm.org>
Link: https://patch.msgid.link/59b94997565032bc9870044f021214a2ed6df213.1781228815.git.m@maowtm.org
[mic: Fix comment formatting]
Signed-off-by: Mickaël Salaün <mic@digikod.net>