instant-messengers: delist Riot (#1047)

We previously added a warning on privacy concerns in #1024 after
Prism-break had delisted Riot and *Notes on privacy and data collection
of Matrix.org* was released revealing concerns even with self-hosted
homeservers.

Today Libre Monde has released another part on privacy investigation on
Matrix.org [1] revealing that they aren't GDPR compliant nor privacy
friendly and behave shadily such as by announcing removal of data as a
result of GDPR request. [2]

[1]:https://github.com/libremonde-org/paper-research-privacy-matrix.org/blob/master/part2/README.md
[2]:https://github.com/libremonde-org/paper-research-privacy-matrix.org/blob/master/part2/README.md#the-request

Closes #1048, closes #1050.

_includes/sections/instant-messenger.html

@@ -21,22 +21,6 @@ <h1 id="im" class="anchor"><a href="#im"><i class="fas fa-link anchor-icon"></i>
 %}
 
 
-{% include cardv2.html
-title="Riot.im"
-image="/assets/img/tools/Riot.png"
-description="Riot.im is a decentralized free-software chatting application based on the <a href\"https://matrix.org/\">Matrix</a> protocol, a recent open protocol for real-time communication offering E2E encryption. It can bridge other communications via others protocols such as IRC too. <a href=\"https://github.com/vector-im/riot-web/issues/6779\"><span class=\"badge badge-warning\" data-toggle=\"tooltip\" title=\"The end-to-end encryption is currently in beta and the mobile client states 'End-to-end encryption is in beta and may not be reliable. You should not yet trust it to secure data.'\">Experimental <i class=\"far fa-question-circle\"></i></a></span> <a href=\"https://gist.github.com/maxidorius/5736fd09c9194b7a6dc03b6b8d7220d0\"<span class=\"badge badge-danger\" data-toggle=\"tooltip\" title=\"Riot sends a lot of data to matrix.org and vector.im with default settings that aren't trivial to change, also with selfhosted homeservers\">Privacy concerns</span></a>"
-website="https://riot.im/"
-forum="https://forum.privacytools.io/t/discussion-riot-im/665"
-github="https://github.com/vector-im"
-android=""
-ios=""
-mac=""
-windows=""
-linux=""
-web=""
-%}
-
-
 {% include cardv2.html
 title="Wire"
 image="/assets/img/tools/wire.png"

source_code.md

@@ -114,8 +114,6 @@ Backend: closed-source
 ## Encrypted Instant Messenger
  Signal https://github.com/signalapp
 
- Riot: https://github.com/vector-im
-
  Ricochet: https://github.com/ricochet-im/ricochet
 
    Worth Mentioning: