chg: dev: Add option to compile named with static linking and LTO

Statically linking lib{isc,dns,ns,cfg,isccc} and enabling LTO shows over 10% improvements on all almost measurements in perflab. That said, we can't use Meson's option for LTO since it would result in every binary being compiled with LTO and a great increase in compile time.

To work around it, we add a configuration option that enables LTO and static linking only for the `named` binary.

Merge branch 'alessio/meson-lto-v2' into 'main'

See merge request isc-projects/bind9!10761