Fixes bug related to Cwriter missing, places Nemesys only on amd64 nodes & added Role for prometheus

We encountered 3 issues, that this merge request fixes:

• Cwriter was used in nemesys.py but not imported or installed
• Nemesys should only be placed on amd64 nodes, since no arm64/v8 image is available
• Nemesys couldn't list pods in the namespace monitoring due to missing permissions