[Tests-Only] Add TrashbinContext to local acceptance tests

[phil-davis]

Local API tests are getting:

https://cloud.drone.io/owncloud/ocis/1317/3/7

148 scenarios (143 passed, 5 undefined)
1118 steps (1092 passed, 21 undefined, 5 skipped)
3m58.15s (15.84Mb)

--- FeatureContext has missing steps. Define them with these snippets:

    /**
     * @Given as :arg1 file :arg2 should exist in the trashbin
     */
    public function asFileShouldExistInTheTrashbin($arg1, $arg2)
    {
        throw new PendingException();
    }
...

Trashbin tests were introduced in #489 but TrashbinContext was not added.

[phil-davis]

Note: CI should fail when this happens - that needs looking into - issue owncloud/core#37853

[phil-davis]

Local API acceptance tests are good: https://cloud.drone.io/owncloud/ocis/1318/3/7

148 scenarios (148 passed)
1118 steps (1118 passed)
3m38.76s (16.15Mb)
runsh: Total 148 scenarios (148 passed, 0 failed)
runsh: Exit code of main run: 0
runsh: There were no unexpected failures.
runsh: There were no unexpected success.