Implement Off-the-Record support for Instantbird with minimalistic user interface
Our goal for June 15 was to have Off-the-Record (OTR) conversations working in Instantbird, but with a minimalistic user interface (UI) that does not support configuring keys yet. Extending the UI will be done later in this project. We accomplished this goal by May 22, despite #11532 (closed) not being done yet. Instructions for compiling an Instantbird version with basic OTR support are available, as is a screenshot of a chat session using OTR. That concludes this task. Arlo did the coding, Karsten helped with the testing.