Add TCP checks on top of HTTP checks

I've been trying Goldpinger out recently, and have been finding it useful already. I was looking through the code, and was curious why you chose to do http monitoring, rather than tcp or icmp pings?

No files, tests, or entry points are named in the issue. Start by locating the existing HTTP monitoring path in Goldpinger and determine how a TCP check would fit the connectivity display; done should include TCP checks alongside the current HTTP checks and verification that the results are reported correctly.

Written by the indexing model from the issue text.