Added LazyDataLoader Functionality

[rohithpudari]

Description

• Added LazyDataLoader class which takes in a lazily evaluated sequence of elements.
• Added Test file for LazyDataLoader Class
• refactored CycleRequestTests file closes #182

Affected Dependencies

None

How has this been tested?

LazyDataLoaderTests added. (more tests to be added after libtorch support for cpu devices)

Checklist

• [X] I have followed the Contribution Guidelines and Code of Conduct
• [X] I have commented my code following the OpenMined Styleguide
• [X] I have labeled this PR with the relevant Type labels
• [X] My changes are covered by tests

[codecov[bot]]

Codecov Report

Merging #197 (8086fec) into dev (d5db664) will decrease coverage by 0.54%. The diff coverage is 0.00%.

@@            Coverage Diff             @@
##              dev     #197      +/-   ##
==========================================
- Coverage   46.02%   45.48%   -0.55%     
==========================================
  Files          21       22       +1     
  Lines        2351     2379      +28     
==========================================
  Hits         1082     1082              
- Misses       1269     1297      +28     

Impacted Files	Coverage Δ
SwiftSyft/Classes/LazyDataLoader.swift	0.00% <0.00%> (ø)

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[rohithpudari]

@mjjimenez yes, removed LazyRandomIterator and used default Sequence iterator