Use certutil to create certificate chain for Git

What does this MR do?

Uses certUtil library to pull the complete certificate chain - which doesn't happen by default in newer Go versions.

Why was this MR needed?

Because without all the certs we can't upgrade from Go 1.8.7

Are there points in the code the reviewer needs to double check?

Does this MR meet the acceptance criteria?

• Documentation created/updated
• Added tests for this feature/bug
• In case of conflicts with master - branch was rebased

What are the relevant issue numbers?

Closes #4019 (closed)