Support web proxy https_proxy environment variable

[n2qz]

Is your feature request related to a problem? Please describe.
checkov does not run behind a web proxy. Instead, it hangs indefinitely trying to connect to https://www.bridgecrew.cloud/api/v1

Describe the solution you'd like
Add web proxy support for proxy indicated in https_proxy environment variable.

Describe alternatives you've considered
None

Additional context
Before patch behind a web proxy:

$ time timeout 5m checkov -d .

real    5m0.007s
user    0m0.504s
sys     0m0.082s
$

After patch behind a web proxy:

$ time timeout 5m checkov -d .

       _               _
   ___| |__   ___  ___| | _______   __
  / __| '_ \ / _ \/ __| |/ / _ \ \ / /
 | (__| | | |  __/ (__|   < (_) \ V /
  \___|_| |_|\___|\___|_|\_\___/ \_/

by bridgecrew.io | version: 1.0.484


real    0m1.547s
user    0m0.938s
sys     0m0.089s
$