added config field and hook

[yeniatencio]

Ticket: https://digital-vic.atlassian.net/browse/SDPAP-9240

BE testing link: https://nginx-php.pr-408.content-reference-sdp-vic-gov-au.sdp4.sdp.vic.gov.au/

Steps:

1. Added new field in the site taxonomy.
2. Add an update hook to roll out the updates for existing site.
3. Updated behat test.
4. Dev-tools commit hash to avoid behat test failing. (Will remove it once this pr is approved)

[anthony-malkoun]

Looks good @yeniatencio. One thing I'd like to see us get into the habit of (or maybe automate somehow) is having this run against a couple of different sites so we know the hook runs ok. But that's for future Yeni :)