cli: introduce new cli command - scan namespace

[chenk]

it is required to introduce a cli command:
starboard scan namespace <namespace name>

• the command will trigger logic for:

• Retrieve all supported resources in the namespace and use the following scanners to scan the resources (in cluster)

  • Vulnerability scanning
  • config-audit scanning

• Scanning should be done in a synchronous way and return output at the end of the scanning in the following formats:

  • console (table) , by default (#1097)
  • json format
  • yaml format