Infinite no chat_id set when group is created and updated to supergroup before enabling private message handling

[Mikaela]

1. Create a group and add the bot there (while it's running).
2. Update the group to a supergroup.
3. Enable Implement private messaging #257 ( { ircChan: 'bot', tgGroup: 'tg group name' }
4. Restart the bot and there is a flood of "no chat_id set" until something is said.

To the original issue text about looping messages with IRC, solution is also adding tgGroupReadOnly: true.

[themiron]

liking ircbot account with tg group means any message from tg group is about to be relayed as message from irc bot to some contact, and unless you specify "<irc_nick> msg" it's unknown to whom irc bot should send that.
but sure, infinite loop with 2+ users should not happen, gonna check and fix if necessary

[Mikaela]

Fix is tgGroupReadOnly: true in the group config, so I will rename this issue more appropiately and also edit the text.