replace welcome, activity, and createroom plugins with communitybot (#34)

data/plugins/thirdparty/communitybot.yaml

@@ -0,0 +1,19 @@
+# The name of the plugin.
+name: Communitybot
+# A link to the Git repository.
+repo: https://github.com/williamkray/maubot-communitybot
+# The SPDX license identifier for the plugin (same as in maubot.yaml)
+license: MIT
+# The author of the plugin.
+author: William Kray
+# A short description for the plugin. May contain markdown.
+description: |
+    helps admins manage a matrix space, with user management, room creation
+    tools, and much more! replaces activity-tracker, createroom, and welcome
+    plugins.
+# Antifeature identifiers. Currently the only defined value is `synchronous`,
+# which must be included if the plugin uses non-async libraries in the main
+# thread (because that can block the whole maubot process).
+antifeatures: []
+# List of public bot user IDs where the plugin is running.
+public_instances: []