use PortManagementSupport mixin to reserve port in #register

[yaauie]

Uses the PortManagementSupport mixin from logstash-plugins/logstash-mixin-port_management_support#1 to reserve a port in #register so that the plugin will fail to start if the port is unavailable.

Resolves the TCP input's expression of elastic/logstash#17703

[jsvd]

I don't think we need to use blocks here since we're not wrapping behavior:

Suggested change

	@port_reservation = port_management.reserve(addr: @host, port: @port) do |reserved_addr, reserved_port|
	@loop = InputLoop.new(@id, reserved_addr, reserved_port, DecoderImpl.new(@codec, self), @tcp_keep_alive, java_ssl_context)
	end
	port_management.reserve(port: @port) # if this succeeds, there is a reservation for the port
	@loop = InputLoop.new(@id, @host, @port, DecoderImpl.new(@codec, self), @tcp_keep_alive, java_ssl_context)

Also we should set the reservation scope for the port alone. Not sure if it's worth differentiating the addr, we can be conservative here and allow the port to be reserved regardless of the addr.

[jsvd]

Could we just do:

Suggested change

	@port_reservation.convert do |reserved_addr, reserved_port|
	@logger.info("Starting tcp input listener", :address => "#{reserved_addr}:#{reserved_port}", :ssl_enabled => @ssl_enabled)
	@loop.start
	end
	@loop.wait_until_closed
	@logger.info("Starting tcp input listener", :address => "#{@host}:#{@port}", :ssl_enabled => @ssl_enabled)
	port_management.release(port: @port) { @loop.run }

Essentially tell the global manager:

1. ok I'm here.
2. release the port but don't free the reservation until I'm out?