Documentation: add contributing information

Hello there!
I decided to create a patch from my drafts so this information
will not be lost. It still needs some attention.

It is a good idea to have the documentation in one place.
For us this means that information from these pages
https://spectrum-os.org/contributing.html, https://spectrum-os.org/participating.html
-- should be moved here https://spectrum-os.org/participating.html.

What I did particularly:

1. Added a new chapter "Contributing".
Copied here the information from here https://spectrum-os.org/contributing.html,
adapting a bit to Spectrum Docs.
2. Moved the "Building Documentation" section from "Development" to "Contributing".
3. In the "Contributing" chapter you can find the following structure:
- Communication in Spectrum (copied from https://spectrum-os.org/participating.html)
- Documentation Style Guide
- Building Documentation

I tried to fix all cross-reference links, so this new content can be used right now.
Any further updates are very welcome.

Signed-off-by: Jenni Nikolaenko <evgeniia.nikolaenko@unikie.com>
Message-Id: <20230119154307.28303-1-evgeniia.nikolaenko@unikie.com>
Reviewed-by: Alyssa Ross <hi@alyssa.is>
Signed-off-by: Alyssa Ross <hi@alyssa.is>

1 files changed, 89 insertions, 0 deletions

diff --git a/Documentation/contributing/communication.adoc b/Documentation/contributing/communication.adoc
new file mode 100644
index 0000000..bb8aeb9
--- /dev/null
+++ b/Documentation/contributing/communication.adoc
@@ -0,0 +1,89 @@
+= Communication in Spectrum
+:description: Channels, announcements and so on.
+:page-nav_order: 1
+:page-parent: Contributing
+
+// SPDX-FileCopyrightText: 2023 Unikie
+// SPDX-License-Identifier: GFDL-1.3-no-invariants-or-later OR CC-BY-SA-4.0
+
+There are several places online in which announcements,
+discussion, and collaboration happen. Rather than tell
+you about them all at once, though, it is best to tell you
+which ones are relevant to you, given how you would like
+to participate (or not) in the project.
+
+Our primary methods of communication are mailing lists and IRC.
+If this is not how you are used to interacting with free
+software projects, *DON'T PANIC*.
+
+We provide instructions for how to get started, and several
+different interfaces for you to choose from depending on what workflow
+(web, mail, Atom, etc.) makes you most comfortable. Details of these
+will be explained further on, but first, you should figure out what
+communication channels are actually relevant for you.
+
+If you are interested in keeping up to date with announcements from
+Spectrum's developers, subscribe to *announce@spectrum-os.org*.
+You can discuss Spectrum and related topics in real time on IRC, or
+more long-form on spectrum-announce (_discuss@spectrum-os.org_).
+Finally, development work happens in Spectrum's
+xref:https://spectrum-os.org/git/[source repositories], and is
+discussed on spectrum-devel (_devel@spectrum-os.org_).
+
+
+== Internet Relay Chat
+
+There is a single Internet Relay Chat (IRC) channel,
+xref:ircs://irc.libera.chat:6697/spectrum[spectrum:libera.chat]
+on xref:https://libera.chat/[Libera.Chat], for all kinds of Spectrum
+discussions.You can also join through xref:https://matrix.org/[Matrix] as
+xref:https://matrix.to/#/#spectrum:libera.chat[spectrum:libera.chat].
+If you are new to IRC, you might find Matrix the easiest way to get started.
+The channel is *logged*, but the logs are not available online yet.
+
+
+== Mailing Lists
+
+If you are interested in participating in the project, or even just
+following along with it, the best thing to do is subscribe to one or
+more of the Spectrum mailing lists.
+
+If mailing lists are not your thing, that is okay! Try the
+xref:https://spectrum-os.org/lists/hyperkitty/[Web UI], which allows
+you to interact with the mailing lists much like a modern web forum.
+
+Each list has xref:https://spectrum-os.org/lists/archives/[archives]
+that can also be accessed via the web, NNTP or Atom. You are strongly
+encouraged to mirror them.
+
+[cols="1,1"]
+|===
+
+|announce@spectrum-os.org
+|This is a one-way list where announcements
+from Spectrum's developers will be posted.
+
+You can subscribe
+xref:https://spectrum-os.org/lists/mailman3/lists/announce.spectrum-os.org/[on the web],
+or by sending mail to *announce-subscribe@spectrum-os.org*.
+
+|discuss@spectrum-os.org
+|This list contains high-level discussion about the project.
+
+You can subscribe
+xref:https://spectrum-os.org/lists/mailman3/lists/discuss.spectrum-os.org/[on the web],
+or by sending mail to *discuss-subscribe@spectrum-os.org*.
+
+|devel@spectrum-os.org
+|This list is where low-level technical discussions happen,
+and where patches are sent.
+
+There is a separate guide for the Spectrum development process,
+including how patches are sent to this list and discussed.
+For more information, see
+xref:../development/working-with-patches.adoc[Working with Patches].
+
+You can subscribe
+xref:https://spectrum-os.org/lists/mailman3/lists/devel.spectrum-os.org/[on the web], or by sending mail to *devel-subscribe@spectrum-os.org*.
+
+|===