Instead of updating hostname manualy on Config DB hostname change,
simply share containers UTS namespace with host OS.
Ideally, instead of setting `--uts=host` for every container in SONiC,
this setting can be set per container if feature requires.
One behaviour change is introduced in this commit, when `--privileged`
or `--cap-add=CAP_SYS_ADMIN` and `--uts=host` are combined, container
has privilege to change host OS and every other container hostname.
Such privilege should be fixed by limiting containers capabilities.
Signed-off-by: Stepan Blyschak <stepanb@mellanox.com>
ee84dca683