Do not promote the IRC channel anymore

Reasons:
- freenode is now officially™ evil
- nobody of our core members is inside this channel
- some visitor told us last week, that mentioning of IRC on
  our page is very confusing, when we actually only use matrix

content/dezentrale.md

@@ -112,12 +112,6 @@ die sie schreiben.
 <div class="pure-g">
     <div class="pure-u-1-2 centered">
 <h3>Chat</h3>
-<div>
-  <a href="{{< value "chat" "irc_href" >}}">
-    {{< value "chat" "irc_channel" >}}
-  </a>
-  {{< value "chat" "irc_server" >}}
-</div>
 <div>
   <a href="{{< value "chat" "matrix_href" >}}">
     {{< value "chat" "matrix_channel" >}}

data/values.yaml

@@ -21,9 +21,6 @@ phone:
   href: tel:+49221596193719
   number: '+49 221 – 596 193 719'
 chat:
-  irc_channel: '#dezentrale'
-  irc_href: irc://freenode.net/dezentrale
-  irc_server: freenode.net
   matrix_channel: '#Eingangsbereich'
   matrix_href: https://matrix.to/#/!ccImuEvBqBFIdXANcK:chat.dezentrale.space
   matrix_server: chat.dezentrale.space
@@ -43,4 +40,4 @@ links:
   meetup_href: https://www.meetup.com/dezentrale
   meetup_name: Meetup
   techniksprechstunde_href: https://techniksprechstunde.de
-  techniksprechstunde_name: Techniksprechstunde
+  techniksprechstunde_name: Techniksprechstunde