[Learners] Explore caching using nscd (name service cache daemon) for DNS caching

**MicroByte Title:** Exploring Caching

**Improvement Proposal:** 
Current DNS cache based activity is based on default system-d resolve.
Adding a activity for nscd based DNS caching would definitely be a great idea to work on.

**Benefits of proposed improvements:** 
1. Learners will learn to work on new dns based tools like nscd