The "--experimental" option was removed in commit f6cca741ea. Using this
deprecated option now causes Scylla to fail with the error:
```
error: the argument ('on') for option '--experimental-features' is invalid
```
So, in this change, let's update the docker entry point script to use
`--experimental-features` command line option instead. The related
document is updated accordingly.
Fixesscylladb/scylladb#22207
Signed-off-by: Kefu Chai <kefu.chai@scylladb.com>
Closesscylladb/scylladb#22283
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