Added the surface area calculation for a pyramid

[DannyMu4]

In the maths > Area.java file, I added a function that allows for the calculation of the surface area for a pyramid.

[codecov-commenter]

Codecov Report

❌ Patch coverage is 0% with 7 lines in your changes missing coverage. Please review.
✅ Project coverage is 77.97%. Comparing base (8930369) to head (605a2c5).

Files with missing lines	Patch %	Lines
src/main/java/com/thealgorithms/maths/Area.java	0.00%	7 Missing ⚠️

Additional details and impacted files

@@             Coverage Diff              @@
##             master    #6898      +/-   ##
============================================
- Coverage     78.00%   77.97%   -0.04%     
+ Complexity     6444     6443       -1     
============================================
  Files           737      737              
  Lines         21519    21526       +7     
  Branches       4208     4209       +1     
============================================
- Hits          16785    16784       -1     
- Misses         4062     4069       +7     
- Partials        672      673       +1     

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