p1: /v2/scrape, /v1/fetch, auth, CLI, contract tests

Single Fetcher.Fetch on the Guard that holds DenyPrefixes. skipTlsVerification
is ignored. No 502. keys add writes the secret only to --out. Release binary
has no -test-allow-prefix.

vendor/github.com/JohannesKaufmann/html-to-markdown/v2/converter/status.go

@@ -0,0 +1,8 @@
+package converter
+
+type RenderStatus int
+
+const (
+	RenderTryNext RenderStatus = iota
+	RenderSuccess
+)