Create Shell_Sort implementation in Python

[subhahu123]

• Please follow the Contributing Guidelines & naming conventions in the guidelines accordingly. 🙂
• Following naming guidelines is important to maintain consistency.😊
• Please NOTE: In case, same implementation of an algorithm is submitted by someone else and it gets accepted, then your contribution won't be merged ( to avoid duplicates )

[niharika412]

I would like to do this!

[indracs7]

Created a pull request #256 for this issue.
@subhahu123