provision: delay initialization of secrets until provision time

when we create the DO 1-click image, the key also gets snapshotted.

https://community.letsencrypt.org/t/receiving-expiration-emails-for-dozens-of-domains/165441

src/server.js

@@ -6,7 +6,6 @@ exports = module.exports = {
 };
 
 const assert = require('assert'),
-    blobs = require('./blobs.js'),
     cloudron = require('./cloudron.js'),
     constants = require('./constants.js'),
     database = require('./database.js'),
@@ -380,7 +379,6 @@ async function start() {
 
     await database.initialize();
     await settings.initCache(); // pre-load very often used settings
-    await blobs.initSecrets();
     await cloudron.initialize();
     await util.promisify(gHttpServer.listen.bind(gHttpServer))(constants.PORT, '127.0.0.1');
     await safe(eventlog.add(eventlog.ACTION_START, { userId: null, username: 'boot' }, { version: constants.VERSION })); // can fail if db down