BE: Respect system proxy settings in WebClient

[Khrol]

HTTP(S) proxy settings are applied only in some specific cases when configureSsl is called with some non-null params. They should be always used.

GithubReleaseInfo is not executed properly in our environment.

• Breaking change? (if so, please describe the impact and migration path for existing application instances)

What changes did you make? (Give an overview)

Is there anything you'd like reviewers to focus on?

How Has This Been Tested? (put an "x" (case-sensitive!) next to an item)

• No need to
• Manually (please, describe, if necessary)

Checked this branch on our production env:

• Unit checks
• Integration checks
• Covered by existing automation

Checklist (put an "x" (case-sensitive!) next to all the items, otherwise the build will fail)

• I have performed a self-review of my own code
• I have commented my code, particularly in hard-to-understand areas
• I have made corresponding changes to the documentation (e.g. ENVIRONMENT VARIABLES)
• My changes generate no new warnings (e.g. Sonar is happy)
• I have added tests that prove my fix is effective or that my feature works
• New and existing unit tests pass locally with my changes
• Any dependent changes have been merged

Check out Contributing and Code of Conduct

A picture of a cute animal (not mandatory but encouraged)