feat(deploy,olm): Allow installing previous (non-latest) versions of RHDH operator from catalog

[pmacik]

Currently, only latest version of RHDH operator that is available in the given channel of a given subscription (OLM) can be installed with the framework.

This PR:

• allows for installing a specific version of the operator from a given catalog (by specifying the RHDH_OLM_OPERATOR_VERSION variable)
• extracts some common functions into a separated and shared common.sh script

[openshift-ci]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: pmacik

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[openshift-ci]

Skipping CI for Draft Pull Request.
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