Document extractor service (#15665)

* Document extractor service

* Fixing vendor modules

* Addressing PR Review comments

* Some small simplifications

* Fixing a linter complain

* simplifying a bit the code using package variables

Co-authored-by: Mattermod <mattermod@users.noreply.github.com>

vendor/github.com/PuerkitoBio/goquery/go.mod

@@ -0,0 +1,8 @@
+module github.com/PuerkitoBio/goquery
+
+require (
+	github.com/andybalholm/cascadia v1.1.0
+	golang.org/x/net v0.0.0-20200202094626-16171245cfb2
+)
+
+go 1.13