[FEATURE] OPA: Page Objects + Opa.resetConfig()

Provide the capability of page objects in OPA, including an example.
This should be the new way to foster reuse of arrangements, actions and
assertions.

Allowing to reset the Opa.config to its default.

Change-Id: I3374d8a99bf130f369e5c3e50026e741e5a1fd84
Merge "[FEATURE] OPA: Page Objects + Opa.resetConfig()"