Maintain CapsLock, NumLock and ScrollLock of keyboard

Currently, CapsLock, NumLock and ScrollLock would keep the state in
KeyboardInputMapper. It cause 2 problems:

1. If user reattach the hardware keyboard, the state would be reset.
2. If there are multiple hardware keyboards, we can't make them
consistent.

We need to store them in the global state and notify others if there
is some state changed.

- Store the meta state of CapsLock, NumLock and ScrollLock in InputReader.
- Set NumLock default on.

Bug: 141329037
Test: atest inputflinger_tests
Change-Id: I3ff5e9d25ed76466a86080350f00d39d6db57c8c