Add support for p4a --feature option

See https://github.com/kivy/python-for-android/pull/2322

buildozer/default.spec

@@ -90,6 +90,9 @@ fullscreen = 0
 # (list) Permissions
 #android.permissions = INTERNET
 
+# (list) features (adds uses-feature -tags to manifest)
+#android.features = android.hardware.usb.host
+
 # (int) Target Android API, should be as high as possible.
 #android.api = 27
 

buildozer/targets/android.py

@@ -1051,6 +1051,11 @@ class TargetAndroid(Target):
             permission = '.'.join(permission)
             build_cmd += [("--permission", permission)]
 
+        # add features
+        features = config.getlist('app', 'android.features', [])
+        for feature in features:
+            build_cmd += [("--feature", feature)]
+
         # android.entrypoint
         entrypoint = config.getdefault('app', 'android.entrypoint', 'org.kivy.android.PythonActivity')
         build_cmd += [('--android-entrypoint', entrypoint)]