Add Decimal_To_Octal

[sachincool]

What Changes does this PR introduce?

Adds Octal To Decimal inside Kotlin And Octal To Decimal as well

What issue have you fixed?

https://github.com/DSC-Chitkara/Algo-DS/issues/9

If relevant, have you updated the README file?

NO

Have you added your name to CONTRIBUTORS.md?

YES

Have you added tests for your code?

Yes

Any other information?

It's not a Bug , It's a Feature .

[the-cybersapien]

Cool! Add extensions to your files as well, and then we're done :smile:

[sachincool]

done @the-cybersapien :100: