Add Strassen Matrix Multiplication algorithm

[hoplite2k]

Describe your change:

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

References

Fixes issue #2488

Checklist:

• I have read CONTRIBUTING.md.
• This pull request is all my own work -- I have not plagiarized.
• I know that pull requests will not be merged if they fail the automated tests.
• All new Java files are placed inside an existing directory.
• All filenames are in all uppercase characters with no spaces or dashes.
• All functions and variable names follow Java naming conventions.
• If this pull request resolves one or more open issues then the commit message contains Fixes: #{$ISSUE_NO}.

[hoplite2k]

Hello @siriak! Your review is much appreciated.

[siriak]

LGTM, only one comment :)

[siriak]

Build is failing
./DivideAndConquer/StrassenMatrixMultiplication.java:4: error: class Strassen is public, should be declared in a file named Strassen.java
public class Strassen {

[hoplite2k]

Hello @siriak! I have resolved the build failure. Can you please check
Thank you