Modify Insertion sort implementation to classical one + add function insertion-sentinel sort.

[NarekDW]

Describe your change:

1. Current implementation of Insertion sort is not the classic one, which is described here - wikipedia
2. Add additional function sentinelSort which is the modification of classical implementation, faster one.
3. Add isSorted function to SortUtils class.
4. Add SortUtilsRandomGenerator class to be able to generate random values and arrays. (It could be extended with additional functions)
5. Add unit tests.

• [x] Add an algorithm?
• [x] Fix a bug or typo in an existing algorithm?
• [ ] Documentation change?

References

Checklist:

• [x] I have read CONTRIBUTING.md.
• [x] This pull request is all my own work -- I have not plagiarized.
• [x] I know that pull requests will not be merged if they fail the automated tests.
• [x] This PR only changes one algorithm file. To ease review, please open separate PRs for separate algorithms.
• [x] All new Java files are placed inside an existing directory.
• [x] All filenames are in all uppercase characters with no spaces or dashes.
• [x] All functions and variable names follow Java naming conventions.
• [x] All new algorithms have a URL in its comments that points to Wikipedia or other similar explanation.
• [x] If this pull request resolves one or more open issues then the commit message contains Fixes: #{$ISSUE_NO}.