Added user level build setting for excluding arm64 simulators

[mjjimenez]

This is needed due to pod dependencies that don't exclude the arm64 simulators themselves (libtorch, GoogleWebRTC ...)

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

[codecov[bot]]

Codecov Report

Merging #195 into dev will decrease coverage by 0.12%. The diff coverage is n/a.

@@            Coverage Diff             @@
##              dev     #195      +/-   ##
==========================================
- Coverage   46.02%   45.89%   -0.13%     
==========================================
  Files          21       21              
  Lines        2351     2351              
==========================================
- Hits         1082     1079       -3     
- Misses       1269     1272       +3     

Impacted Files	Coverage Δ
SwiftSyft/Classes/SyftClient.swift	82.13% <0.00%> (-0.80%)	:arrow_down:

---

Continue to review full report at Codecov.

Legend - Click here to learn more Δ = absolute <relative> (impact), ø = not affected, ? = missing data Powered by Codecov. Last update 7edd27d...e8154bd. Read the comment docs.