fix: respect common env variables

[zFernand0]

What It Does

Fixes #346.
Added support for commonly used environmental variables, like REQUESTS_CA_BUNDLE and CURL_CA_BUNDLE

How to Test

1. Make sure you can run a sample command against an LPAR with valid certificates
   • print((console.issue_command("D T"))['cmd-response'])
2. Setup a proxy that will function as your custom Certificate Authority.
   • Steps: Proxy configuration
3. Specify the proxy as an environmental variable (either in your python script or in the command line)
   • HTTPS_PROXY=https://myproxy.company.net:3129 python test.py
   • Notice the [SSL: CERTIFICATE_VERIFY_FAILED] error
4. Specify either of the commonly used CA bundle variables with the proper certificate chain combination
   • REQUESTS_CA_BUNDLE=/path/to/combo.crt
   • CURL_CA_BUNDLE=/path/to/combo.crt
   • Note: The combo.crt refers to the complete certificate chain (proxyCA, intermediate/LPAR, global/root)
   • The command should work as expected

Review Checklist
I certify that I have:

• tested my changes
• added/updated automated tests
• updated the changelog
• followed the contribution guidelines

Additional Comments

The same can be achieved today using the SSL_CERT_FILE environmental variable

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 89.09%. Comparing base (4661f83) to head (c3fa843).
Report is 10 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #347      +/-   ##
==========================================
- Coverage   89.10%   89.09%   -0.02%     
==========================================
  Files          65       65              
  Lines        3258     3255       -3     
==========================================
- Hits         2903     2900       -3     
  Misses        355      355              

Flag	Coverage Δ
unittests	89.09% <100.00%> (-0.02%)	⬇️

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[traeok]

Changes look good to me, thanks for the fix Fernando!

[t1m0thyj]

LGTM, thanks @zFernand0!

[zFernand0]