Add the option to have temporary messages

Problem

Currently, there is no way to have temporary messages in Fluxer. Given the rise in AI systems that collect user data to build profiles for surveillance purposes, I believe it is necessary to implement countermeasures. Since it is extremely easy to gather information from users through their messages simply by joining a community and reading them, or by using malicious bots or scrapers, a viable solution would be the ability to create temporary messages. This could be configured as a global profile setting, applied per community, or set at the chat channel level. Also it would be great for privacy reasons.

Proposed solution

Implement the option to send temporary messages, with settings available globally, per community, per text chat, or in private messages.