Throttle httpclient requests in Pip and SimplePip

[Omotola]

This pr uses semaphore to reduce the amount of http requests to 10 concurrent requests at a time in both pip and simplepip. This is to avoid httpclient timing out due to too many requests at a time.

The fix also seems to have made the cd scan run faster. It was initially taking over 30 minutes to run on the vienna repo locally, but after throttling the requests the scan is taking about 23 minutes.

[codecov]

Codecov Report

Merging #847 (b168a9e) into main (ae50a41) will increase coverage by 0.0%.
Report is 8 commits behind head on main.
The diff coverage is 75.0%.

@@          Coverage Diff          @@
##            main    #847   +/-   ##
=====================================
  Coverage   77.4%   77.5%           
=====================================
  Files        235     235           
  Lines       9933    9956   +23     
=====================================
+ Hits        7696    7720   +24     
+ Misses      2237    2236    -1     

Files	Coverage Δ
...ft.ComponentDetection.Detectors/pip/IPyPiClient.cs	64.3% <75.0%> (+0.2%)	⬆️
...mponentDetection.Detectors/pip/SimplePypiClient.cs	89.4% <75.0%> (-0.4%)	⬇️

... and 2 files with indirect coverage changes