android: migrate app build system to use gradle

Most of the Android specific meson code has been removed and replaced with
the grade build system.

The new meson build scripts build and move the libmpd.so binaries into the correct
location that gradle expects. After than gradle handles building the rest of the Android app.

Icons and banners have been updated for the modern app packaging expectations.

For reference here was the figma template Google provides that I used to back the png versions
for older versions of Android <https://www.figma.com/community/file/1283953738855070149>

android/app/src/main/res/values/ic_banner_background.xml

@@ -0,0 +1,4 @@
+<?xml version="1.0" encoding="utf-8"?>
+<resources>
+    <color name="ic_banner_background">#FFFFFF</color>
+</resources>

android/app/src/main/res/values/ic_launcher_background.xml

@@ -0,0 +1,4 @@
+<?xml version="1.0" encoding="utf-8"?>
+<resources>
+    <color name="ic_launcher_background">#FFFFFF</color>
+</resources>

android/app/src/main/res/values/strings.xml

@@ -0,0 +1,12 @@
+<?xml version="1.0" encoding="utf-8"?>
+
+<resources>
+  <string name="app_name">MPD</string>
+  <string name="notification_title_mpd_running">Music Player Daemon is running</string>
+  <string name="notification_text_mpd_running">Touch for MPD options.</string>
+  <string name="toggle_button_run_on">MPD is running</string>
+  <string name="toggle_button_run_off">MPD is not running</string>
+  <string name="checkbox_run_on_boot">Run MPD automatically on boot</string>
+  <string name="checkbox_wakelock">Prevent suspend when MPD is running (Wakelock)</string>
+  <string name="checkbox_pause_on_headphones_disconnect">Pause MPD when headphones disconnect</string>
+</resources>