Runners setup time increasing due to PS modules installation #873

Description

GH runners take some time to set up due to an increasing list of PS modules to be installed.
Most of the modules are required only for the removal step.

The required set of PS modules could be installed based on the job type to save running time

e.g. 'Az.CognitiveServices' is needed by the runner executing the deployment validation in order to remove soft deleted resources. It is not needed for Pester tests. Hence it shouldn't be installed on the runner executing Pester but only on the one executing the deployment validation.