Added Books for Go, Added few interactive tutorial websites (#6421)

* Added Books for Go, Added interactive tutorials

Added Go succintly which is freely available on the mentioned website.

Added Go Web Development Succintly which is freely available on the
mentioned website.

Added interactive tutorial websites learn-golang.org, learn-html.org,
learnsqlonline.org

* Added suggested changes

* Added Expos Guide in books for Operating Systems

* Added more details on expos
Co-authored-by: NDavid Ordás <3125580+davorpa@users.noreply.github.com>
Co-authored-by: NDavid Ordás <3125580+davorpa@users.noreply.github.com>

books/free-programming-books-langs.md

@@ -814,6 +814,8 @@ That section got so big, we decided to split it into its own file, the [BY SUBJE
 * [Go Bootcamp](http://www.golangbootcamp.com/book) - Matt Aimonetti
 * [Go by Example](https://gobyexample.com)
 * [Go for Javascript Developers](https://github.com/bulim/go-for-javascript-developers)
+* [Go Succinctly](https://www.syncfusion.com/succinctly-free-ebooks/go-succinctly) - Mark Lewin (PDF, EPUB, Kindle)
+* [Go Web Development Succinctly](https://www.syncfusion.com/succinctly-free-ebooks/go-web-development) - Mark Lewin (PDF, EPUB, Kindle)
 * [How To Code in Go](https://www.digitalocean.com/community/books/how-to-code-in-go-ebook) - Mark Bates, Cory Lanou, and Timothy J. Raymond (PDF, EPUB)
 * [Learn Go with Tests](https://quii.gitbook.io/learn-go-with-tests/)
 * [Learning Go](https://miek.nl/go/)

more/free-programming-interactive-tutorials-en.md

@@ -249,6 +249,7 @@
 #### Operating systems
 
 * [Learning operating system development using Linux kernel and Raspberry Pi](https://github.com/s-matyukevich/raspberry-pi-os) - Sergey Matyukevich (:construction: *in process*)
+* [Project eXpOS: eXperimental Operating System](https://exposnitc.github.io) - Dr. Murali Krishnan K., Department of Computer Science and Engineering of the Calicut National Institute of Technology (HTML)
 
 
 ### LaTeX