chore: Add down gem for Local file downloads (#2765)

- Add down gem to handle downloading files to host machine
- Remove the LocalResource class
- Introduce max limit for contact avatars send via SDK

Gemfile

@@ -35,6 +35,8 @@ gem 'commonmarker'
 gem 'json_schemer'
 # Rack middleware for blocking & throttling abusive requests
 gem 'rack-attack'
+# a utility tool for streaming, flexible and safe downloading of remote files
+gem 'down', '~> 5.0'
 
 ##-- for active storage --##
 gem 'aws-sdk-s3', require: false