Add drop duplicates C++ example

[srinivasyadav18]

Description

This PR adds drop duplicates C++ example using distinct API with four different keep options.
The example source file uses a csv file containing bank transactions of customers on a single day, for building and processing the table using distinct algorithm.

Checklist

• I am familiar with the Contributing Guidelines.
• New or existing tests cover these changes.
• The documentation is up to date with these changes.

[GregoryKimball]

Thank you @srinivasyadav18 this looks like a perfect start!

• Would you please add the filename as a CLI parameter that defaults to this transactions.csv file?
• Would you please use the simple timer from the other examples and add console prints for the wall time of distinct calls?
• Question: should we convert this to JSON so that we can benchmark nested types?

[GregoryKimball]

We are closing this in favor of presenting performance data from stream compaction nvbenchmarks.