DNS introducer should support alternative ports

[nextsux]

As some VPS are blocking port 8444 (yes, I'm looking at you Hetzner!) it would be nice if we can run nodes on alternative ports.

Currently it's possible to run node on other port, even it can introduce itself correctly with that port.
Unfortunately DNS introducer responds with A records:

$ dig dns-introducer.chia.net A +short
114.253.82.136
94.231.123.46
113.218.242.227
49.168.187.113
23.240.237.173
124.162.248.150
184.82.141.124
178.221.96.132
122.57.157.200
192.180.98.66
51.68.155.46
69.146.18.160
101.182.38.73
178.34.180.16
112.117.188.198
119.129.97.68
205.250.208.45
1.80.228.168
188.6.138.4
14.39.165.165
114.206.198.70
82.55.224.248
95.170.185.178
185.148.3.170
211.195.191.184
148.101.40.59
113.13.240.93
193.106.208.182
86.52.238.17
61.38.251.63
202.65.92.65
178.117.240.144

It would be nice if Chia could support discovery of alternative port nodes for example using SRV or TXT records