Replace Twitter link in footer with BlueSky social (#3107)

* Replace X link in footer with BlueSky social

* Include attribution for bluesky SVG

* Update SVG to be correct size and colour

* Add reuse-compatible license file

navigation.toml

@@ -108,9 +108,9 @@ relMe = true
 newTab = true
 
 [[footer_external]]
-image = "x.svg"
+image = "bluesky.svg"
-alt = "Matrix on X"
+alt = "Matrix on BlueSky"
-href = "https://x.com/matrixdotorg"
+href = "https://bsky.app/profile/matrix.org"
 newTab = true
 
 [[footer_external]]

static/assets/bluesky.svg

@@ -0,0 +1,11 @@
+<!-- This icon originated from https://commons.wikimedia.org/wiki/File:Bluesky_Logo.svg -->
+<?xml version="1.0" encoding="UTF-8"?><svg
+   width="27px"
+   height="24px"
+   xmlns="http://www.w3.org/2000/svg">
+  <path
+     d="m 5.8526068,1.615495 c 3.095485,2.346093 6.4250312,7.102992 7.6474722,9.65582 1.222534,-2.55264 4.551894,-7.309774 7.647473,-9.65582 C 23.38109,-0.07735119 27,-1.3871796 27,2.780764 c 0,0.832395 -0.47273,6.99255 -0.74999,7.992627 -0.963755,3.47696 -4.475643,4.363776 -7.599525,3.827034 5.460485,0.93823 6.849581,4.045988 3.849666,7.153747 -5.697433,5.902241 -8.188866,-1.480894 -8.827552,-3.372723 -0.117031,-0.346817 -0.171794,-0.509061 -0.172599,-0.3711 -8.1e-4,-0.137966 -0.05557,0.02428 -0.172599,0.3711 -0.638406,1.891829 -3.129794,9.275152 -8.8275522,3.372723 -2.999961,-3.107759 -1.610912,-6.215705 3.849666,-7.153747 -3.123975,0.536742 -6.63591,-0.350079 -7.59952495,-3.827034 C 0.47272085,9.77322 -1.5106201e-7,3.613065 -1.5106201e-7,2.780764 -1.5106201e-7,-1.3871796 3.6190028,-0.07735119 5.8524478,1.615495 Z"
+     fill="currentColor"
+     viewBox="0 0 27 24"
+     />
+</svg>

static/assets/bluesky.svg.license

@@ -0,0 +1,3 @@
+SPDX-FileCopyrightText: Eric Bailey, Public domain, via Wikimedia Commons
+
+SPDX-License-Identifier: CC0-1.0

static/assets/x.svg

@@ -1,3 +0,0 @@
-<!-- This icon is part of the X brand toolkit.
-     The source is available at https://about.x.com/en/who-we-are/brand-toolkit -->
-<svg xmlns="http://www.w3.org/2000/svg" width="24px" height="24px" viewBox="0 0 24 24" fill="currentColor"><path d="M14.234 10.162 22.977 0h-2.072l-7.591 8.824L7.251 0H.258l9.168 13.343L.258 24H2.33l8.016-9.318L16.749 24h6.993l-9.508-13.838Zm-2.837 3.299-.929-1.329L3.076 1.56h3.182l5.965 8.532.929 1.329 7.754 11.09h-3.182l-6.327-9.05Z"/></svg>