[FEATURE REQUEST][GSoC 2020] Add Omnichannel Livechat Trigger option for when user opens the chat window

[dlassalle]

Usually when the widget is first opened to a text dialog, its a blank box without an agent present. Only when the user types their first message does it route to an agent.

Add an option enabling agents (and bots) to type first. For example, when a user opens the widget for the first time, they see a message from the bot saying "Thanks for contacting us, please describe your issue"

Ideally, we would also update the option to be able to impersonate a specific agent or department queue

[renatobecker]

@dlassalle We already support Livechat trigger messages, so you can, for instance, set a condition like Visitor time on site = 5 seconds, and then send a message to the livechat user.
Anyway, when the user returns, the trigger messages are not sent so we may need to improve the trigger messages feature in order to work properly in some cases like that.

[dlassalle]

Ah I see, I'll adjust this issue to reflect that