feat: extensions check + resolver

server/core/kernel.js

@@ -40,6 +40,7 @@ module.exports = {
         inbound: new EventEmitter(),
         outbound: new EventEmitter()
       }
+      WIKI.extensions = require('./extensions')
     } catch (err) {
       WIKI.logger.error(err)
       process.exit(1)
@@ -76,6 +77,8 @@ module.exports = {
     await WIKI.models.searchEngines.refreshSearchEnginesFromDisk()
     await WIKI.models.storage.refreshTargetsFromDisk()
 
+    await WIKI.extensions.init()
+
     await WIKI.auth.activateStrategies()
     await WIKI.models.commentProviders.initProvider()
     await WIKI.models.searchEngines.initEngine()