gplugin/gplugin

Expose the GPluginManager class

2021-06-18, Gary Kramlich
2b8af6f9b838
Expose the GPluginManager class

This is the first step in converting to the manager paradigm we've been using
in pidgin.

Testing Done:
Ran the unit tests. This currently breaks the vapi bindings for the manager, but nothing is using them right now so it's okay and will be fixed in a follow up pull request.

Reviewed at https://reviews.imfreedom.org/r/689/
The following individuals have contributed to this project.
Ankit Vani <a@nevitus.org>
EionRobb <eion@robbmob.com>
Elliott Sales de Andrade <quantum.analyst@gmail.com>
Gary Kramlich <grim@reaperworld.com>
Jason Scherer <schereja@gmail.com>
John Bailey <rekkanoryo@rekkanoryo.org>
Mike Ruprecht <cmaiku@gmail.com>
Olaf Hering <olaf@aepfle.de>
Richard Laager <rlaager@pidgin.im>
Sorvival <sorvival@tutanota.com>