Add Creative Commons Attribution 3.0 license

This license is used for many presentation recordings. It would be great
to have the license supported by the application directly and avoid
constantly looking for the license link.

src/ui/constants/licenses.js

@@ -1,4 +1,8 @@
 export const CC_LICENSES = [
+  {
+    value: 'Creative Commons Attribution 3.0',
+    url: 'https://creativecommons.org/licenses/by/3.0/legalcode',
+  },
   {
     value: 'Creative Commons Attribution 4.0 International',
     url: 'https://creativecommons.org/licenses/by/4.0/legalcode',