[docsy] Configure Google Custom Search Engine but leave it disabled

[chalin]

NOTE: as mentioned in subsequent comments, I can't get GCSE to work fully under the current CSP, so I've decided to leave in the partial code changes, but disable search entirely for now, until we find & agree upon a viable search solution.

• Contributes to [docsy] Enable site search #91
• Console access: https://programmablesearchengine.google.com/controlpanel/overview?cx=06ecafa260afd40f9
• Notes: /cc @nate-double-u @JustinCappos
  • Adds cse.google.com as CSP enabled domain
  • @chalin added projects@cncf.io as an owner of the GCSE

[chalin]

Got this implementation working at 80%, but Google is using JS eval for each search entry, it seems :-/

I'm not finding a clean way to support GCSE, so I'm going to put this in draft mode for now, until @JustinCappos chimes in. If we don't even want to use GCSE for this website, then I'll close this PR, and disable search until someone has time to enable offline search.