fix: remove broid.ai (website down, no development since 2018-02, no activity on issue tracker)

README.md

@@ -260,7 +260,6 @@ _CalDAV or CardDAV clients._
 
 ### Custom communication systems
 
-- [Broid](https://broid.ai) - Broid enables rich conversations on all messaging channels within a single schema integration using W3C standards. ([Demo](https://www.broid.ai), [Source Code](https://github.com/broidHQ/integrations)) `AGPL-3.0` `Nodejs`
 - [Centrifugo](https://github.com/centrifugal/centrifugo) - Language-agnostic real-time messaging (Websocket or SockJS) server. ([Demo](https://github.com/centrifugal/centrifugo#demo)) `MIT` `Go`
 - [Cherry](https://github.com/rafael-santiago/cherry) - Tiny webchat server. `GPL-2.0` `Go`
 - [Freenet](https://freenetproject.org/index.html) - Anonymously share files, browse and publish "freesites" (web sites accessible only through Freenet) and chat on forums. ([Source Code](https://github.com/freenet/fred)) `GPL-2.0` `Java`