Hide header option

This patch add extra setting to hide the header of the view

Thanks for the work on this! A few things:

1. Can this be converted to a merge request to make it easier to review and comment please? + so tests run
2. This needs test coverage, which can be added to ViewsReferenceSettingsTest.php

Patch #2 did not work for me, in my case there was no value in $view->display_handler->options['header']. I believe $view->display_handler->getOption('header') would be a good choice and safe option.

Opened MR that includes test coverage for hide header option and the above change. Needs review. Thanks!

Great stuff, thank you! Did a round of manual testing as well and all working as expected. Thank you for adding the test coverage as well.