Test support: Return list of AppWrappers

[sutaakar]

Also adding clients for image operations and dynamic client.

Issue link

N/A

What changes have been made

Adding support functionality for opendatahub-io/distributed-workloads#103
Adding a function to return AppWrappers based on name prefix, also creation of temporary file with content.

Verification steps

N/A

Checks

• I've made sure the tests are passing.
• Testing Strategy
  • Unit tests
  • Manual tests
  • Testing is not required for this change

[astefanutti]

/lgtm

[sutaakar]

Self approving as nobody else reacts and I need this merged for follow up PR
/approve

[openshift-ci]

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