mysql-connector: add config options for selecting data source

and load SQL data source during plugin init

src/datasource-zabbix/config.controller.js

@@ -0,0 +1,28 @@
+import _ from 'lodash';
+
+const SUPPORTED_SQL_DS = ['mysql'];
+
+const defaultConfig = {
+  dbConnection: {
+    enable: false,
+  }
+};
+
+export class ZabbixDSConfigController {
+  /** @ngInject */
+  constructor($scope, $injector, datasourceSrv) {
+    this.datasourceSrv = datasourceSrv;
+
+    _.defaults(this.current.jsonData, defaultConfig);
+    this.sqlDataSources = this.getSupportedSQLDataSources();
+  }
+
+  getSupportedSQLDataSources() {
+    let datasources = this.datasourceSrv.getAll();
+    return _.filter(datasources, ds => {
+      return _.includes(SUPPORTED_SQL_DS, ds.type);
+    });
+  }
+}
+
+ZabbixDSConfigController.templateUrl = 'datasource-zabbix/partials/config.html';