Add n8n configuration hint for better Telegram performance

Suggestion:

Update Telegram Node documentation and Telegram-related tutorials about improving performance with the environmental variable EXECUTIONS_PROCESS=main

https://docs.n8n.io/integrations/nodes/n8n-nodes-base.telegram/

Why?

As it was mentioned by n8n-team somewhere on this forum, creating Telegram bots wasn’t the main purpose of the tool. However, this use case turned out to be very convenient. But here’s a catch - the default n8n installation is too slow for the real-time responses.

It was mentioned on the forum and in the documentation that spawning a node.js process takes about 1 sec. While it may be true on certain hardware settings, the usual inexpensive VPS-s from different providers take 5-10 seconds to initiate. This statistic is based on my experience and a feedback from users of one n8n-related chat.

5-10 seconds seem fine for most users, but in a situation when chatbots are created by non-IT people, it can be a deal breaker. I think adding a hint on how to configure n8n installation to improve performance for this particular use case will help users to adopt n8n.