replace dep with go modules (#16017)

- guide shamelessly stolen from prometheus/prometheus
- updates local interface of oauth exchange
- updates local impl of hclogger
- bump jaeger client version

closes #16088

vendor/github.com/prometheus/client_golang/api/client.go

@@ -30,10 +30,10 @@ import (
 // DefaultRoundTripper is used if no RoundTripper is set in Config.
 var DefaultRoundTripper http.RoundTripper = &http.Transport{
 	Proxy: http.ProxyFromEnvironment,
-	Dial: (&net.Dialer{
+	DialContext: (&net.Dialer{
 		Timeout:   30 * time.Second,
 		KeepAlive: 30 * time.Second,
-	}).Dial,
+	}).DialContext,
 	TLSHandshakeTimeout: 10 * time.Second,
 }