Add focus mode adjustment and exposure support

[Eiffelyk]

1. Add long press to lock focus
2. Exposure adjustment, when the focus mode is manual focus, can manually adjust the exposure

If I don't explain it clearly, you can open the system camera and see the focus mode and exposure adjustments

thanks

[ujizin]

Hey @Eiffelyk, my apologies for the delay!

I'm currently working on exposure adjustment and will strive to release it ASAP. After this, I'll work on lock focus.

Thank you for opening the issue! 😄