Add certificate name for windows code-signing (#1513)

* Add certificate name for windows code-signing

electron-builder supports our extended validation code-signing cert, but
only on windows. Our release process must now include a signing step on
windows.

FREEBIE

* AppVeyor Remove certificateSubjectName to disable signing

* Move code-signing disable package.json updates above build

* AppVeyor: Use temporary holding file for package.json changes

package.json

@@ -75,6 +75,7 @@
     "win": {
       "asarUnpack": "node_modules/spellchecker/vendor/hunspell_dictionaries",
       "artifactName": "${productName}-Setup_${version}.${ext}",
+      "certificateSubjectName": "Signal",
       "icon": "build/icons/win/icon.ico",
       "publish": {
         "provider": "s3",