Add Flutter UI Succinctly eBook Resource (#6337)

* Add Python 3 Book

Python 3 book from DigitalOcean.

* Update list to add learning Processing resource

Reattempted.

* Update podcasts-screencasts-en.md

Changed playlist and added the contributor name.

* Alphabetize Processing playlists

Alphabetize the processing playlists added.

* Removed Processing Resource

Removed Processing YouTube links from screencasts.

* Updated free-courses with Processing Resource

Added processing resource in free courses list.

* Update free-courses-en.md Readme

Added Deno course from freeCodeCamp.

* Update free-courses-en.md

Removed Deno resource from master branch.

* Add Flutter UI Succinctly Book

Added a new Flutter UI eBook from the Syncfusion website.

* Fixed Flutter UI resource 

Changed Flutter UI resource to alphabetical order.

books/free-programming-books-langs.md

@@ -720,6 +720,7 @@ That section got so big, we decided to split it into its own file, the [BY SUBJE
 * [Flutter Succinctly, Syncfusion](https://www.syncfusion.com/ebooks/flutter-succinctly) (PDF, Kindle) (email address *requested*, not required)
 * [Flutter Tutorial](https://www.tutorialspoint.com/flutter) - Tutorials Point
 * [Flutter Tutorials Handbook](https://kodestat.gitbook.io/flutter)
+* [Flutter UI Succinctly, Syncfusion](https://www.syncfusion.com/succinctly-free-ebooks/flutter-ui-succinctly) - Ed Freitas
 
 
 ### Force.com