Added Resources for Blockchain And Solidity (HacktoberFest) (#5973)

* Added free-programming-playgrounds for Solidity

* Added free-programming-interactive-tutorials-en for Solidity

* Update free-programming-interactive-tutorials-en.md

* Added free-programming-cheatsheets for Solidity

* Added free-courses-en for Blockchain

* Update free-courses-en.md

* Update free-courses-en.md

* Update free-courses-en.md

* Update free-programming-cheatsheets.md

* Update free-programming-cheatsheets.md

* Update free-programming-cheatsheets.md

* Update free-courses-en.md

* Update free-programming-playgrounds.md

* Update free-programming-cheatsheets.md

* Update free-programming-interactive-tutorials-en.md

* Update free-programming-playgrounds.md

* Recover deleted Manoj Ramesh resource

Co-authored-by: David Ordás <3125580+davorpa@users.noreply.github.com>

* Update more/free-programming-playgrounds.md

Co-authored-by: David Ordás <3125580+davorpa@users.noreply.github.com>

* add creator

Co-authored-by: David Ordás <3125580+davorpa@users.noreply.github.com>

Co-authored-by: Eric Hellman <eric@hellman.net>
Co-authored-by: David Ordás <3125580+davorpa@users.noreply.github.com>

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

@@ -41,6 +41,7 @@
 * [Rust](#rust)
 * [Scala](#scala)
 * [Selenium](#selenium)
+* [Solidity](#solidity)
 * [SQL](#sql)
 * [Vim](#vim)
 
@@ -339,6 +340,11 @@
 * [Selenium Tutorial - Web Automation](http://www.techbeamers.com/selenium-webdriver-tutorial)
 
 
+### Solidity
+
+* [CryptoZombies.io](https://cryptozombies.io) - Loom Network
+
+
 ### SQL
 
 * [Intro to SQL: Querying and managing data](https://www.khanacademy.org/computing/computer-programming/sql) - Khan Academy