Explore more websites for optional integration

[shatgupt]

Explore more websites which can be optionally supported by the extension to run code.
I am going to keep this issue open for suggestions to add to the following list.

• http://xahlee.info/comp/comp_lang_tutorials_index.html [Python2, Python3, Ruby, Go, PHP, Java]
• http://www.learntosolveit.com [C, Python, Ruby, Java, Scala]
• https://www.geeksforgeeks.org [C, C++, Java, Python]
  Example: https://www.geeksforgeeks.org/kth-smallestlargest-element-unsorted-array-set-2-expected-linear-time/
• https://www.tutorialspoint.com/tutorialslibrary.htm [C, C++, Python2/3, Ruby, Go, PHP, Java, Scala]
• Sites at https://github.com/ronreiter/interactive-tutorials/tree/master/tutorials
  Not suitable for RMCO since the snippets are not standalone programs.

[shatgupt]

Xahlee is implemented: #10.
Adds a Run button below code.

Screenshots

Python 2

Python 3

Ruby

Golang

PHP

Java

[shatgupt]

Learn To Solve It is implemented: #12.
Updates the Run this button to use RunMyCode Online.

Screenshots

C

Python

Ruby

Java

[shatgupt]

GeeksForGeeks is implemented: #14
Adds a Run Here button.

Screenshots

C

Python3

Java

[shatgupt]

Tutorialspoint is implemented: #15.
Adds a Run Here button.

Screenshots

C

C++

Python

Ruby

Java

Scala