Public api changes to namespace accounts & connection. (#2383)

* 1.Added following functions to namespace accounts
function getAllAccounts(): Thenable<AccountWithProviderHandle[]>;
function getSecurityToken(account: AccountWithProviderHandle): Thenable<{}>;
2.Added class AccountWithProviderHandle as the wrapper for Account
3.Changed function openConnectionDialog of namespace connection to allow connection dialog initialized with specified parameters, i.e., server name, database name, etc.
function openConnectionDialog(provider?: string[], initialConnectionProfile?: IConnectionProfile): Thenable<connection.Connection>;

* Added unit tests for ExtHostAccountManagement.$getAllAccounts

src/sql/workbench/api/node/mainThreadAccountManagement.ts

@@ -46,6 +46,10 @@ export class MainThreadAccountManagement implements MainThreadAccountManagementS
 		this._accountManagementService.accountUpdated(updatedAccount);
 	}
 
+	public $getAccountsForProvider(providerId: string): Thenable<sqlops.Account[]> {
+		return this._accountManagementService.getAccountsForProvider(providerId);
+	}
+
 	public $registerAccountProvider(providerMetadata: sqlops.AccountProviderMetadata, handle: number): Thenable<any> {
 		let self = this;