feat: add functionality to register plugins via http

Also:

- Add functionality for serving the responses from plugins
- Add tests for related methods and routes

Closes #2, #37

src/storage/elasticsearch/elasticsearch.ts

@@ -174,7 +174,6 @@ export class Elasticsearch implements Database {
   constructor(private readonly config: SCConfigFile, mailQueue?: MailQueue) {
 
     if (typeof config.internal.database === 'undefined'
-      || typeof config.internal.database.version === 'undefined'
       || typeof config.internal.database.version !== 'string') {
       throw new Error('Database version is undefined. Check your config file');
     }
@@ -182,14 +181,10 @@ export class Elasticsearch implements Database {
     const options: ES.ConfigOptions = {
       apiVersion: config.internal.database.version,
       host: Elasticsearch.getElasticsearchUrl(),
-      log: 'error',
+      // enable verbose logging for all request to elasticsearch
+      log:  process.env.ES_DEBUG === 'true' ? 'trace' : 'error',
     };
 
-    // enable verbose logging for all request to elasticsearch
-    if (process.env.ES_DEBUG === 'true') {
-      options.log = 'trace';
-    }
-
     this.client = new ES.Client(options);
     this.aliasMap = {};
     this.ready = false;