Add metadata filter to flaps list

[rugwirobaker]

No description provided.

[benbjohnson]

This isn't separating out URL parameters with a &. A better approach would be to just use url.Values so it can handle encoding too. Also,it doesn't look like state is even used by any of the callers of List() so you could just remove it.

q := make(url.Values)
for k, v := range metadata {
	q.Set("metadata." + k, v)
}

var getEndpoint = ""
if len(q) > 0 {
	getEndpoint = "?" + q.Encode()
}