feat: Add badges for F-Droid & Obtainium installation

Signed-off-by: celenity <celenity@celenity.dev>

README.md

@@ -5,6 +5,13 @@
         height="200">
 </p>
 
+[<img src="assets/f-droid.png"
+    alt="Get it on F-Droid"
+    height="80">](fdroidrepos://fdroid.ironfoxoss.org/fdroid/repo?fingerprint=C5E291B5A571F9C8CD9A9799C2C94E02EC9703948893F2CA756D67B94204F904)
+[<img src="assets/obtainium.png"
+    alt="Get it on Obtainium"
+    height="80">](obtainium://app/%7B%22id%22%3A%22org.ironfoxoss.ironfox%22%2C%22url%22%3A%22https%3A%2F%2Ffdroid.ironfoxoss.org%2Ffdroid%2Frepo%2F%22%2C%22author%22%3A%22IronFox%20OSS%22%2C%22name%22%3A%22IronFox%22%2C%22additionalSettings%22%3A%22%7B%5C%22appIdOrName%5C%22%3A%5C%22org.ironfoxoss.ironfox%5C%22%2C%5C%22pickHighestVersionCode%5C%22%3Afalse%2C%5C%22trackOnly%5C%22%3Afalse%2C%5C%22versionExtractionRegEx%5C%22%3A%5C%22%5C%22%2C%5C%22matchGroupToUse%5C%22%3A%5C%22%5C%22%2C%5C%22versionDetection%5C%22%3Atrue%2C%5C%22releaseDateAsVersion%5C%22%3Afalse%2C%5C%22useVersionCodeAsOSVersion%5C%22%3Afalse%2C%5C%22apkFilterRegEx%5C%22%3A%5C%22%5C%22%2C%5C%22invertAPKFilter%5C%22%3Afalse%2C%5C%22autoApkFilterByArch%5C%22%3Atrue%2C%5C%22appName%5C%22%3A%5C%22%5C%22%2C%5C%22shizukuPretendToBeGooglePlay%5C%22%3Afalse%2C%5C%22exemptFromBackgroundUpdates%5C%22%3Afalse%2C%5C%22skipUpdateNotifications%5C%22%3Afalse%2C%5C%22about%5C%22%3A%5C%22IronFox%20is%20a%20secure%2C%20hardened%20and%20privacy-oriented%20web%20browser%20for%20Android%2C%20based%20on%20Firefox.%5C%22%7D%22%2C%22overrideSource%22%3A%22FDroidRepo%22%7D)
+
 ------------
 
 IronFox is a fork of [Divested Computing Group](https://divested.dev/)'s [Mull Browser](https://divestos.org/pages/our_apps#mull), based on [Mozilla Firefox](https://www.mozilla.org/firefox/). **Our goal is to continue the legacy of Mull by providing a free and open source, privacy and security-oriented web browser for daily use.**