Provide error callbacks

[maxim-kukushkin]

Currently if the bot faces any general issues (like network errors while listening to updates), it writes its own log entries. For example:

Mar 10, 2023 1:25:07 AM com.pengrad.telegrambot.impl.UpdatesHandler$1 onFailure
INFO: Update listener failure
java.net.UnknownHostException: api.telegram.org
<...>

First of all it seems to use its own logger, not slf4j, which results in a different formatting than the rest of the app.

However, the main request is:

Would it be possible to set a custom events callback which will be invoked when it fails to connect or restores the connection? So that the application could provide its own logging/suppress the errors/etc., etc.

In this case the current logging that the bot does could be the default callback. However, if it's overridden by the app, then the app's callback is invoked instead.

[Stas Parshin]

There's ExceptionHandler

bot.setUpdatesListener(new UpdatesListener() {
    @Override
    public int process(List<Update> updates) {
        return UpdatesListener.CONFIRMED_UPDATES_ALL;
    }
}, new ExceptionHandler() {
    @Override
    public void onException(TelegramException e) {
    }
});

[maxim-kukushkin]

Thanks!
Like I mentioned in the other issue, may be you can consider adding an example in the sample code or the documentation?