Add Bitrix24Accounts documentation

Created a new documentation file for the Bitrix24Accounts in the Application Contracts. This documentation includes an account state diagram and a detailed breakdown of repository methods. Each method is explained with its associated use cases to aid in understanding and implementation.

Signed-off-by: mesilov <[email protected]>

src/Application/Contracts/Bitrix24Accounts/Exceptions/Bitrix24AccountNotFoundException.php

@@ -0,0 +1,11 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Bitrix24\SDK\Application\Contracts\Bitrix24Accounts\Exceptions;
+
+use Bitrix24\SDK\Core\Exceptions\BaseException;
+
+class Bitrix24AccountNotFoundException extends BaseException
+{
+}