[6.15.z] Add case for special chars in HTTP proxy password

[Satellite-QE]

Cherrypick of PR: #14538

Problem Statement

We are missing coverage for a BZ where the HTTP proxy is created with a user containing special characters in his password.

Solution

Not only we need to create the proxy at the Satellite side, we also need to create the user at the proxy side to verify the content operations actually work. In the end I decided to create such users dynamically during the test run, so I needed to add a new ProxyHost class with a few functions to handle that. The class is instantiated in a session-scoped fixture and used in test and other fixture.

PRT test Cases example

trigger: test-robottelo
pytest: tests/foreman/ui/test_http_proxy.py -k special

[Satellite-QE]

trigger: test-robottelo
pytest: tests/foreman/ui/test_http_proxy.py -k special

[Satellite-QE]

PRT Result

Build Number: 6249
Build Status: UNSTABLE
PRT Comment: pytest tests/foreman/ui/test_http_proxy.py -k special --external-logging
Test Result : =========== 1 failed, 7 deselected, 5 warnings in 795.06s (0:13:15) ============

[vsedmik]

trigger: test-robottelo
pytest: tests/foreman/ui/test_http_proxy.py -k special

[Satellite-QE]

PRT Result

Build Number: 6270
Build Status: SUCCESS
PRT Comment: pytest tests/foreman/ui/test_http_proxy.py -k special --external-logging
Test Result : =========== 1 passed, 7 deselected, 5 warnings in 860.89s (0:14:20) ============