Switch images to svgs, where possible (#1563)

Closes #1361, #1362

_includes/sections/social-news-aggregator.html

@@ -6,7 +6,7 @@
 
 {% include cardv2.html
 title="Aether"
-image="/assets/img/tools/aether.png"
+image="/assets/img/svg/3rd-party/aether.svg"
 description='<a href="https://github.com/nehbit/aether/blob/master/LICENSE.md">Aether is a free and open-source</a> decentralized social news aggregator with a built-in voting system.'
 website="https://getaether.net/"
 forum="https://forum.privacytools.io/t/discussion-aether/1256"
@@ -18,7 +18,7 @@ linux="https://getaether.net/download/"
 
 {% include cardv2.html
 title="Tildes"
-image="/assets/img/tools/tildes.png"
+image="/assets/img/svg/3rd-party/tildes.svg"
 description='Tildes is a web-based self-hostable online bulletin board. It is licensed under <a href="https://gitlab.com/tildes/tildes/blob/master/LICENSE">GPL 3.0</a>.'
 website="https://tildes.net"
 forum="https://forum.privacytools.io/t/discussion-tildes/1257"
@@ -28,7 +28,7 @@ web="https://tildes.net"
 
 {% include cardv2.html
 title="Raddle"
-image="/assets/img/tools/raddle.png"
+image="/assets/img/png/3rd-party/raddle.png"
 description="Raddle is a public Postmill instance focused on privacy and anti-censorship."
 website="https://raddle.me"
 forum="https://forum.privacytools.io/t/discussion-raddle/1258"