feat: require ssl links for new apps

[ckerr]

Fixes #1068.

Adds a test to confirm that all URLs in new apps' yml files are https or sftp.

As with some other tests, here we 'grandfather' in older apps that are already in the repo but which don't follow this requirement.

The new test's warnings look like this:

  153) human-submitted app data
       zoommy
         zoommy.yml
           should use ssl links:
     AssertionError: http://zoommyapp.com/: expected 'http:' to be one of [ 'https:', 'sftp:' ]
      at /home/charles/src/electron/apps/apps/test/human-data.js:103:65
      at Array.forEach (<anonymous>)
      at Context.<anonymous> (test/human-data.js:103:18)
      at processImmediate (internal/timers.js:439:21)

CC @MarshallOfSound

[codebytere]

Would it be more efficient and uniform to simply update the deviant links, perhaps?

[ckerr]

Instead of grandfathering, you mean? Several of the existing links don't work with https.

Interesting idea about winnowing down the list, though. We could fix anything that can be shifted to https.