Add general introduction to Jami

Co-authored-by: Nick Econopouly <wry@mm.st>
Change-Id: I53dec19a68480133b8dbd2796107d2bb39e0210c

general/index.rst

+#######
+General
+#######
+
+This chapter introduces Jami and tries to answer the most common
+questions.
+
+.. toctree::
+   :maxdepth: 1
+
+   introduction

general/introduction.rst

+Introduction
+============
+
+.. image:: ../_static/logo-jami.svg
+   :alt: Jami logo
+
+Jami is a free/libre, end-to-end encrypted and private communication
+platform that requires no central authority.
+
+Jami's features include: text chats, voice and video calls, screen
+sharing, file sharing, conference calls, and group chats (:ref:`coming
+soon <general/technical-overview:swarms>`).  Jami can also function as
+a regular SIP client.
+
+Jami works on GNU/Linux, Windows, macOS, iOS, and Android.  Multiple
+devices can be linked to a Jami account, and no personal information
+is required to create an account.
+
+How does Jami work?
+-------------------
+
+Jami uses a `distributed hash table
+<https://en.wikipedia.org/wiki/Distributed_hash_table>`__ (DHT) to
+connect peers.  Jami accounts are asymmetric `X.509 certificates
+<https://en.wikipedia.org/wiki/X.509>`__ generated by the GnuTLS
+library.  Calls are made over the `Session Initiation Protocol
+<https://en.wikipedia.org/wiki/Session_Initiation_Protocol>`__ (SIP)
+after negotiating a `TLS
+<https://en.wikipedia.org/wiki/Transport_Layer_Security>`__-encrypted
+secure connection, performing `Secure Real-time Transport Protocol
+<https://en.wikipedia.org/wiki/Secure_Real-time_Transport_Protocol>`__
+(SRTP) communication which carries the media streams.
+
+For more on how Jami works, see the `Jami and how it empowers users
+<https://kelar.org/~bandali/talks/libreplanet-2021-jami.html>`__ talk
+by `Amin Bandali <https://kelar.org/~bandali/>`__, as well as the
+:doc:`Technical Overview <technical-overview>` for more in-depth
+information.
+
+Who makes Jami?
+---------------
+
+The Jami project is led by `Savoir-faire Linux
+<https://www.savoirfairelinux.com/en/>`__ -- a Canadian/Québécois
+GNU/Linux consulting company -- and is supported by a global community
+of free software enthusiasts, users, and contributors.
+
+Jami is `free software
+<https://www.gnu.org/philosophy/free-sw.html>`__ and an official
+GNU package, developed and distributed under the `GNU GPLv3+
+<https://www.gnu.org/licenses/gpl-3.0.html>`__ license.

index.rst

@@ -20,4 +20,5 @@ contribute<guides/how-to-contribute-to-this-documentation>`!
 .. toctree::
    :maxdepth: 2
 
+   general/index
    guides/index