Sentry mode: automatically records and plays noise when bumped

[sshane]

• [x] Unarmed when locked/unlocked (just resets timer)
• [x] Unarmed when doors are unlocked
• [x] Fix interaction between thermald and sentryd (thermald needs to respect sentryd's onroad status and set params and power mode accordingly).
  • [x] Since sentryd is 100hz and thermal much lower, we'd have to wait for thermald to set the powersave mode before going onroad. Instead, we set the powersave mode in sentryd and stop thermald from changing it when sentry mode is active.
  • [x] In the future, we should let thermald handle everything from starting processes to setting the powersave mode.