Fancy Kernel r29

- remove discard mount option from /cache (since automatic trimming has been re-introduced)
- revert experimental settings with cpu.rt_runtime_us and sched_rt_runtime_us
- block tweaks
- additions for WiFi drop workaround and automatic /cache trimming
- renice with -18 instead of -17
- add missing $busybox for setting swappiness
- add action launcher to LMK whitelist
- custom LMK values (slightly more aggressive than stock)