show the app's own GPL-3.0 licence and the bundled public suffix list

The app itself and the MPL-2.0 public-suffix data OkHttp embeds fall
outside the automatically collected Gradle dependency list, so add both
via the manual config. The Subtracks entry links to its source.

app/config/libraries/public_suffix_list.json

@@ -0,0 +1,7 @@
+{
+  "uniqueId": "org.publicsuffix:publicsuffix-list",
+  "name": "Public Suffix List",
+  "description": "Domain data bundled inside OkHttp's PublicSuffixDatabase, used to enforce cookie and hostname policy.",
+  "website": "https://publicsuffix.org/",
+  "licenses": ["MPL-2.0"]
+}

app/config/libraries/subtracks.json

@@ -0,0 +1,7 @@
+{
+  "uniqueId": "com.subtracks:next",
+  "name": "Subtracks",
+  "description": "Subtracks itself, a client for Subsonic-compatible servers.",
+  "website": "https://github.com/austinried/subtracks",
+  "licenses": ["GPL-3.0-only"]
+}