Konnect entities: add Konnect mocks for integration testing

[pmalek]

Problem statement

#370 introduces support for managing of Konnect entities in KGO.

Konnect SDK - https://github.com/Kong/sdk-konnect-go/ - instances are created in runtime due to tokens being stored in Kubernetes resources ( KonnectAPIAuthConfiguration or Secrets ).

This issue tracks the effort of introducing mocks for Konnect APIs so that we can test Konnect integration in operator's integration test suite.

Relevant

https://github.com/Kong/gateway-operator/pull/446/files#diff-5b6aadc0fe9b4d0ba8cfd31756eef41ffdcd65687cd077d3b8d427294dcc81b5R157-R164

Acceptance criteria

• Konnect mocks exists and are used in integration tests.