app/matrix: matrix.hackerspace.pl: add libera.chat

Apart from this, we also had to manually edit the registration yaml to
add @libera_ and #libera_ prefixes to the allowlists.

Change-Id: If85f58cf3d1291e0bf9099ef13d9397040a47782
diff --git a/app/matrix/matrix.hackerspace.pl.jsonnet b/app/matrix/matrix.hackerspace.pl.jsonnet
index be947f9..7c022d4 100644
--- a/app/matrix/matrix.hackerspace.pl.jsonnet
+++ b/app/matrix/matrix.hackerspace.pl.jsonnet
@@ -54,12 +54,28 @@
                             port: 1113,
                         },
                         servers+: {
+                            local servers = self,
                             "irc.freenode.net"+: {
                                 mappings+: import "secrets/plain/appservice-irc-freenode-mappings.jsonnet",
                                 ircClients+: {
                                     maxClients: 150,
                                 },
                             },
+                            "irc.libera.chat": servers["irc.freenode.net"] {
+                                mappings: {},
+                                ircClients+: {
+                                    maxClients: 20,
+                                },
+                                name: "Libera Chat",
+                                networkId: "libera",
+                                dynamicChannels+: {
+                                    groupId: "+libera:hackerspace.pl",
+                                    aliasTemplate: "#libera_$CHANNEL",
+                                },
+                                matrixClients+: {
+                                    userTemplate:"@libera_$NICK",
+                                },
+                            },
                         },
                     },
                 },