Adding the HashTable in Data Structures

[Ravikisha]

• [x] I have performed a self-review of my code
• [x] My code follows the style guidelines of this project
• [x] I have added tests that prove my fix is effective or that my feature works
• [x] New and existing unit tests pass locally with my changes
• [x] Comments in areas I changed are up to date
• [x] I have added comments to hard-to-understand areas of my code
• [x] I have made corresponding changes to the README.md

[codecov[bot]]

Codecov Report

All modified lines are covered by tests :white_check_mark:

Comparison is base (8dfab48) 96.03% compared to head (ed865b4) 96.10%.

Additional details and impacted files

```diff @@ Coverage Diff @@ ## master #417 +/- ## ========================================== + Coverage 96.03% 96.10% +0.07% ========================================== Files 231 234 +3 Lines 9665 9843 +178 ========================================== + Hits 9282 9460 +178 Misses 383 383 ``` | [Files](https://app.codecov.io/gh/TheAlgorithms/C-Sharp/pull/417?src=pr&el=tree&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=TheAlgorithms) | Coverage Δ | | |---|---|---| | [DataStructures/Hashing/Entry.cs](https://app.codecov.io/gh/TheAlgorithms/C-Sharp/pull/417?src=pr&el=tree&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=TheAlgorithms#diff-RGF0YVN0cnVjdHVyZXMvSGFzaGluZy9FbnRyeS5jcw==) | `100.00% <100.00%> (ø)` | | | [DataStructures/Hashing/HashTable.cs](https://app.codecov.io/gh/TheAlgorithms/C-Sharp/pull/417?src=pr&el=tree&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=TheAlgorithms#diff-RGF0YVN0cnVjdHVyZXMvSGFzaGluZy9IYXNoVGFibGUuY3M=) | `100.00% <100.00%> (ø)` | | | [DataStructures/Hashing/NumberTheory/PrimeNumber.cs](https://app.codecov.io/gh/TheAlgorithms/C-Sharp/pull/417?src=pr&el=tree&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=TheAlgorithms#diff-RGF0YVN0cnVjdHVyZXMvSGFzaGluZy9OdW1iZXJUaGVvcnkvUHJpbWVOdW1iZXIuY3M=) | `100.00% <100.00%> (ø)` | |

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