Add message action to copy message to input as reply

[mrsimpson]

Motivation

As a developer of a bot, I want to suggest a response to the user. Instead of just making the user to send a fully predefined message, the user shall adjust the message (think of it as a template for the reply).
This reduces typing overhead, reduces errors during the conversation and makes sure the user follows some expected structure

Implementation

There already was a message-action to send a message by clicking a button living in an attachment.
This enhancement allows to create an action button (either from an integration, an API or a bot) which copies a predefined message as template into the message input (browser only!)

Consumption

The button is part of an attachment's actions and can be created anywhere there is a message being created.
Sample for an outgoing integration

class Script{
  
    prepare_outgoing_request({ request }) {

      return {
        message: {
          text: "Would you be so kind to let me know what you did today?",
          attachments: [{
            actions: [
              {
                type: "button",
                msg_in_chat_window: true,
                msg_processing_type: "respondWithMessage",
                text: "Respond easily",
                msg: "**What I worked on today**\n- \n\n**What I am planning to do tomorrow**\n- "
              }
            ]
            }]
        }
      }
    }
}

How it looks like

Sample: A Daily-Bot is gathering input from users:

Open issues

Mobile adaption - since this is a client side action, the mobile apps would have to implement this copy-to-input as well.

[mrsimpson]

Port nach RC core: RocketChat#12626