Use ambient light sensor to tune display brightness in lpm_on state

Add ALS profile configuration for use with lpm_on state. Should stay
relatively dim indoors, saturates to 100% brightness at the same level
as lowest display brightness profile.

Setup a datapipe for communicating lpm brightness changes between display
and brightness filtering plugins.

Set standby override flag for ambient light sensor so that it can be
powered on in lpm_on state too.

[mce] Use ambient light sensor to tune display brightness in lpm_on state. Fixes JB#18791
Remove dead code

Timer based DIM -> LPM_ON transitions are not used anymore.
Explain why standby override is used for proximity and orientation sensors
Merge pull request #166 from spiiroin/lpm_brightness

Use ambient light sensor to tune display brightness in lpm_on state
Bump mce version to 1.30.3