Added PasswordGenerator Program in String Package

[Sarabjeet13]

Implemented a simple password generator using Random class in strings package.

[codecov-commenter]

Codecov Report

❌ Patch coverage is 0% with 10 lines in your changes missing coverage. Please review.
✅ Project coverage is 75.20%. Comparing base (5e9d9f7) to head (b420c9d).
⚠️ Report is 4 commits behind head on master.

Files with missing lines	Patch %	Lines
...a/com/thealgorithms/strings/PasswordGenerator.java	0.00%	10 Missing ⚠️

Additional details and impacted files

@@             Coverage Diff              @@
##             master    #6570      +/-   ##
============================================
- Coverage     75.23%   75.20%   -0.04%     
- Complexity     5626     5627       +1     
============================================
  Files           691      692       +1     
  Lines         19448    19458      +10     
  Branches       3758     3759       +1     
============================================
+ Hits          14632    14633       +1     
- Misses         4248     4258      +10     
+ Partials        568      567       -1     

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[DenizAltunkapan]

I don’t think a password generator qualifies as an algorithm for this repository. It’s more of a utility function...