supervisor scripts for Docker and supervisor scripts for offline
installer are almost same, drop Docker one and share same code to
deduplicate them.
Closes#9143Fixes#9194
Today our docker image is based on Centos7 ,Since centos will be EOL in
2024 and no longer has stable release stream. let's move our docker image to be based on ubuntu 20.04
Based on the work done in https://github.com/scylladb/scylla/pull/8730,
let's build our docker image based on local packages using buildah
Closes#8849