Send "typing" status

[denexapp]

Sometimes handling a command may take a while. It will be a good idea to send "Cute Bot is typing" status when handling of command starts.

• Add the corresponding method to the vk-ts package
• Add "sends message" flag to commands and modes
• Add a global queue for messages: a counter and two methods: imGonnaSend() and send()
• Send "typing" status on errors, commands, and modes