android video service wakelock

[21pages]

#6192
Without using battery optimization, without using lock to avoid background killing, after screen off

• without wakelock: disconnect after 3 minutes
• with wakelock: stay connected for 20 minutes (maybe never disconnect, test later).

The android_context used by android-wakelock needs to be initialized and it should be managed in only one place, otherwise there is a risk of crash. cpal and oboe also use it, and there is no context management in them, which is expected.
https://github.com/sagebind/android-wakelock/blob/master/src/lib.rs#L252
https://github.com/rust-mobile/ndk-context/blob/0eb252bf2306f6ca477430a35e88298e634c0b24/ndk-context/src/lib.rs#L84

move init(this) from onStartCommand to onCreate to look more reasonable, because there is no function like uninit()