Add support for specific APT repository 'Poliverse'

Looks like this repo has some specific security configuration that requires additional configurations to work with  NXRM. 

Setup steps: **  

1. Create Apt proxy in the Nexus repository manager
2. Launch Ubuntu e.g. by docker. docker run -it ubuntu
3. Proceed with instructions from  https://polyverse.com/learn/polymorphic-linux-install-ubuntu-host/
4. File  /etc/apt/sources.list will be updated by a script from step 2 and new repo will be added. 
5. Update /etc/apt/sources.list to point it to Nexus repository manager
6. Perform apt-get update 

Expected: Metadata is fetched from the remote server.
Actual: An 401 error appears in the NXRM logs.