feat: add `bundle.android` config to build and sign the apk file in release mode

[fontlos]

Add this to Dioxus.toml

[bundle.android]
jks_file = "path/to/jks file relative to Dioxus.toml"
jks_password = "jks_password "
key_alias = "key_alias"
key_password = "key_password "

When release flag is enabled and this configuration exists at the same time, use gradlew assembleRelease build and sign apk file