It sort of reverts the 5a97ba7121 commit, because storage service now
uses the cdc generation service to serve raft topo updates which, in
turn, takes the cdc gen. service all over the raft code _just_ to make
it as an argument to storage service topo calls.
Also there's API carrying cdc gen. service for the single call and also
there's an implicit need to kick cdc gen. service on decommission which
also needs storage service to reference cdc gen. after boot is complete
Signed-off-by: Pavel Emelyanov <xemul@scylladb.com>
933ea0afe6