Android <7.0 support

[fr-an-k]

After building an apk, adb install gives INSTALL_PARSE_FAILED_NO_CERTIFICATES.
Looking at the code it seems that V1 signing is not supported (Android <7.0).

In Cargo.toml (is this actually used?):

[package.metadata.android.sdk]
min_sdk_version = 21
target_sdk_version = 34
max_sdk_version = 34

Command:

x build -v --release --format apk --platform android --arch arm64

If I build directly for the device, it decides to make an aab instead of apk (format arg is not allowed).
That's undesirable; I don't use a store and adb doesn't work with this format.

x build -v --release --device 192.168.0.225:5555
adb -s 192.168.0.225:5555 install -r target/x/release/android/na-winit-wgpu.aab
Performing Push Install
adb: need APK file on command line

If I try to run it, it fails:

x run -v --release --device adb:192.168.0.225:5555
Error: adb getprop exited with code Some(1)

On Android 8.1 I can build and run just fine.

[fr-an-k]

If I try to convert the aab to apk, bundletool says:

Error: The archive doesn't seem to be an App Bundle, it is missing required file 'BundleConfig.pb

cargo apk build creates an installable apk (it doesn't work but that's probably because of wgpu)