Create namespaces for specific tests only

[mat-rumian]

Is your feature request related to a problem? Please describe.
In the OpenTelemetry-Operator integration tests there was a need to create additional namespaces used to validate instrumentation-cr creation. Unfortunately in current implementation of the tests additional namespaces are created for each tests in the scope.

Describe the solution you'd like
Have a place in the code where I can create namespace for specific test

Describe alternatives you've considered

Additional context