Mutliple cleanups to Purple.Message
Review Request #3289 — Created July 12, 2024 and submitted
* Reorder a bunch stuff so it is alphabetical * Added purple_message_new and deprecated the other constructors for it. * Added a new author-name property and marked the author property as deprecated for it. * Added new event and notice properties * De-dented get_property and set_property * Turned on warning for deprecated signals and properties in the devenv and purple unit tests. * Added purple_message_set_timestamp_now to set the timestamp to utc now
Cowabunga'd with the turtles.
Sent some messages over dm and channels.