Include external plugins, minor cleanup

- Consolidate plugins from other repositories to make their installation easier
- Make minor changes to improve formatting

README.md

@@ -19,6 +19,10 @@ Alternatively, you can use URLs to raw files to install Python plugins. For exam
 
 See the `/help plugins` command for further plugin management options.
 
+## Plugins description
+
+To be described.
+
 ## Building CProof with plugin support
 
 Dependencies required:
@@ -41,3 +45,12 @@ API Documentation is available on our website, [jabber.space](https://jabber.spa
 - [Python hooks](https://jabber.space/api-reference/python/plugin/)
 - [C API](https://jabber.space/api-reference/c/profapi/)
 - [C hooks](https://jabber.space/api-reference/c/profhooks/)
+
+## External plugins (C)
+
+- [profanity-plugins by Reimar](https://github.com/ReimarPB/profanity-plugins) - Collection of plugins
+
+
+## External plugins (Python)
+
+- [profanity-copy-message-plugin](https://github.com/lonski/profanity-copy-message-plugin) - Copy messages to clipboard.