Chore: Message to support multiple attachments (#730)

* Changes for the message to have multiple attachments
* changed the message association to attachments from has_one to has_many
* changed all the references of this association in building and fetching to reflect this change

* Added number of attachments validation to the message model

* Modified the backend responses and endpoints to reflect multiple attachment support (#737)

* Changing the frontend components for multiple attachments
* changed the request structure to reflect the multiple attachment structures
* changed the message bubbles to support multiple attachments
* bugfix: agent side attachment was not showing because of a missing await
* broken message was shown because of the store filtering
* Added documentation for ImageMagick

* spec fixes

* refactored code to reflect more apt namings

* Added updated message listener for the dashboard (#727)
* Added the publishing for message updated event
* Implemented the listener for dashboard

Co-authored-by: Pranav Raj Sreepuram <pranavrajs@gmail.com>

docs/development/environment-setup/mac-os.md

@@ -99,11 +99,14 @@ launchctl unload ~/Library/LaunchAgents/homebrew.mxcl.redis.plist
 ```
 
 ### Install imagemagick
+Chatwoot uses `imagemagick` library to resize images for showing previews and smaller size based on context.
 
 ```bash
 brew install imagemagick
 ```
 
+You can read more on installing imagemagick from source from [here](https://imagemagick.org/script/download.php).
+
 ### Install Docker
 
 This is an optional step. Those who are doing development can install docker from [Docker Desktop](https://www.docker.com/products/docker-desktop).