Connection Dialog: Dropdown for database name (#583)

* dropdown now lets databases

* show databases for SQL Login too

* localized strings

* removed unnecesssary logic

* fixed dropdown height, case-insensitive filter and alignement

* added cache for connections

src/sql/parts/connection/connectionDialog/connectionDialogService.ts

@@ -43,6 +43,7 @@ export interface IConnectionComponentCallbacks {
 	onCreateNewServerGroup?: () => void;
 	onAdvancedProperties?: () => void;
 	onSetAzureTimeOut?: () => void;
+	onFetchDatabases?: (serverName: string, authenticationType: string, userName?: string, password?: string) => Promise<string[]>;
 }
 
 export interface IConnectionComponentController {