Exposes two options, `path` and `mode`, to configure the location and
permissions on the socket file.
The `mode` needs to be specified as string in octal and will be converted
into a decimal integer, so it correctly passes through the YAML parser
and arrives at the `os.chmod` call in the Twisted codebase. What a fun
detour.
Adds an assertion, that either `path` or `bind_addresses` and `port` are
configured on every listener.
Migrates the default replication listener of the main instance to a UNIX
domain socket, because it is more efficient.
Introduces the `enableRegistrationScript` option, to gracefully disable
the user registration script, when the client listener listens on a UNIX
domain socket, which is something the script does not support.
143d266f0d