Resolve "Renderer application returning always success exit code"

• Related issues: #1335 (closed)
• Requested reviewers: @paulusj

Reason why this change is needed

• The external renderer application has many errors which simply print to output without modifying the returncode. This should be changed.

Description of the change

• Added modification of the returncode

Affected operating points

• External renderer application, returncodes

Related to #1335 (closed)