Set filesystem permissions for the maintenance socket to 660 (previously it was 755) to allow a scyllaadm's group to connect.
Split the logic of creating sockets into two separate functions, one for each case: when it is a regular cql controller or used by maintenance_socket.
Fixes https://github.com/scylladb/scylladb/issues/16487.
Closesscylladb/scylladb#17113
* github.com:scylladb/scylladb:
maintenance_socket: add option to set owning group
transport/controller: get rid of magic number for socket path's maximal length
transport/controller: set unix_domain_socket_permissions for maintenance_socket
transport/controller: pass unix_domain_socket_permissions to generic_server::listen
transport/controller: split configuring sockets into separate functions
93af3dd69b