Delete broken Quora links

[kemonprogrammer]

Description

The questions and answers from quora have been deleted or are otherwise gone.

Changes

• I deleted the following links:

1. https://techiedelight.quora.com/500-Data-Structures-and-Algorithms-practice-problems-and-their-solutions : Page not found - The question has been deleted
2. https://www.quora.com/What-are-the-best-websites-a-programmer-should-visit/answer/Ashish-Padalkar?srid=OH96 : The answer has been deleted

Why quora

I also searched for the links on the Web Archive, but found out, that quora blocks web scrapers like the Web Archive source: https://waxy.org/2018/12/why-you-should-never-ever-use-quora/

Remarks

The first link was also mentioned in #1083 But this pr makes few changes, which should be easy to be verified and approved