[FEATURE] Insert hook into form wizard view

Introduces a hook in tx_form_View_Wizard_Wizard. This hook
allows extending the wizard interface by loading extending
resources. The hook is executed after all other resources have
been loaded and just before content rendering.

Use it by adding your function to the array
$TYPO3_CONF_VARS['EXTCONF']['form']['hooks']['renderWizard']

Change-Id: I4fc22d5044d2808a9dbdb5ea9b256c2427987030
Resolves: #34711
Releases: 6.0
Reviewed-on: http://review.typo3.org/9559
Reviewed-by: Andreas Wolf
Tested-by: Andreas Wolf