first pass at [WB-10211]. Create new empty dir if no reqs found.

[gtarpenning]

Fixes WB-10211

Description

When no requirement file is found, changes the requirement prefix from "" to now create an empty env/ folder so that the docker image build doesn't fail.

Testing

I created a github project with and without a requirements file (different branches)

[codecov[bot]]

Codecov Report

Merging #3989 (d77c529) into master (d77c529) will not change coverage. The diff coverage is n/a.

:exclamation: Current head d77c529 differs from pull request most recent head c5fd466. Consider uploading reports for the commit c5fd466 to get more accurate results

@@           Coverage Diff           @@
##           master    #3989   +/-   ##
=======================================
  Coverage   82.71%   82.71%           
=======================================
  Files         255      255           
  Lines       32266    32266           
=======================================
  Hits        26690    26690           
  Misses       5576     5576           

Flag	Coverage Δ
functest	54.90% <0.00%> (ø)
unittest	73.44% <0.00%> (ø)

Flags with carried forward coverage won't be shown. Click here to find out more.

[gtarpenning]

@KyleGoyette Best way to debug CircleCI testing failures involving cuda (test_launch_cuda_flag)? Might I need access to a cuda enabled machine?

[KyleGoyette]

Good question, if you check the Tests tab on Circle, you can see that one has been marked flakey. Since no real changes have been made to the ticket since things were passing, you can assume that this is flake. You can test this locally to ensure it is indeed flake and if it is, just squash and merge it