Release 1.0.17

Refactor BotApp to manage its own CancellationTokenSource

The constructor of the `BotApp` class in the `TelegramBot` namespace has been modified to remove the `cancellationTokenSource` parameter. Instead, a new `CancellationTokenSource` instance is created within the constructor.

In the `BotBuilder` class within the `TelegramBot.Builders` namespace, the instantiation of `CancellationTokenSource` has been removed, and the `BotApp` constructor is called without passing a `cancellationTokenSource` parameter.

These changes simplify the instantiation process of `BotApp` by encapsulating the creation of `CancellationTokenSource` within the class itself.