make-ca-1.16

• Change the certificate root for Mozilla to Let's Encrypt and adjust the URL to use https://hg-edge.mozilla.org instead of https://hg.mozilla.org. This is required because hg.mozilla.org now permanently redirects to hg-edge.mozilla.org, and the security certificate is now signed by Let's Encrypt. Also of note is that the command used to get the log and certdata.txt had to be adjusted for this change. This should work until 2035, as that is when the root certificate expires. This fixes #34.