ssm-api data persistent on disk

[shakibamoshiri]

at the moment only by restarting the sing-box is possible to write in memory data to disk
check out how to safely flush shadowsocks data to disk when SSM-API enabled #3525

[shakibamoshiri]

in dev-next branch has been fixed
not in stable version yet
https://github.com/SagerNet/sing-box/tree/dev-next/service/ssmapi