This commit extracts the information about the default for tables in keyspace creation
to a separate file in the _common folder. The file is then included using
the scylladb_include_flag directive.
The purpose of this commit is to make it possible to include a different file
in the scylla-enterprise repo - with a different default.
Refs https://github.com/scylladb/scylla-enterprise/issues/4585Closesscylladb/scylladb#20181
