We have an inconsistency where some flags for ports only support the port number as an integer, while others as host:port string (typically defaulted to ":####"). We should probably converge onto the latter format which allows better control over which IP(s) the server will be listening, while also accepting just a number as well.

Example of two types of flags:

--admin-http-port int           The http port for the admin server, including health check, /metrics, etc. (default 14271)
--http-server.host-port string  host:port of the http server (e.g. for /sampling point and /baggageRestrictions endpoint) (default ":5778")

cc @objectiser