Boot time profiling script

[adeebshihadeh]

For boot time, the first priority is anything needed to engage openpilot, and the second is auxiliary stuff a user would notice (wifi, modem, etc.)

Before we start improving boot time, we need a good test. Previous attempts have consistently hit long tail race conditions that led to regressions. This is a more detailed version of #110 (comment).

Requirements:

• Records when a service (e.g. Weston) or peripheral (e.g. DSP) is ready
• Reports if something failed to come up
• Must capture everything openpilot uses and a user would notice: display, GPU, DSP, cameras, modem, Wi-Fi, etc.
• Has a mode to run in a loop and record stats

This script should answer the questions:

• how long until I can engage?
• how long until I can SSH into the device?