It now happens in initialize_virtual_tables(), but this function is split into sub-calls and iterates over virtual tables map several times to do its work. This PR squashes it into a straightforward code which is shorter and, hopefully, easier to read.
Closesscylladb/scylladb#18133
* github.com:scylladb/scylladb:
virtual_tables: Open-code install_virtual_readers_and_writers()
virtual_tables: Move readers setup loop into add_table()
virtual_tables: Move tables creation loop into add_table()
virtual_tables: Make add_tablet() a coroutine
virtual_tables: Open-code register_virtual_tables()