Feat: Add banners as a type of campaign

[aw-0]

Is your feature request related to a problem? Please describe.
Yes. My project uses Chatwoot (love it, by the way), and I use the live chat campaign feature a lot for marketing. However, when we'd like to make a site-wide announcement, the normal "send a message via the live chat" doesn't seem to cut it for UX.

Describe the solution you'd like
An option to display a campaign as a banner (e.x. see https://www.intercom.com/blog/announcing-banners/ and the image below). This is a much better way to create site-wide announcements instead of mass sending messages through live chat.

Describe alternatives you've considered
Very few live chat solutions support banners (let alone open-source and self-hostable), and my project doesn't have the budget to use a solution like Intercom to do marketing.

Additional context
Example for a selection dropdown: