Log fatal CEF crashes to file

[WizardCM]

Description

CEF provides no method to reroute logging, but without FATAL logging it is impossible to track down some crashes.

This outputs FATAL-level logging to debug.log in the obs-browser user data directory.

Motivation and Context

We don't ship CEF symbols so some crashes become impossible to track down. By logging fatal errors, we can get some insight.

How Has This Been Tested?

Launched OBS on Windows. Verified the debug.log contained an error after a crash.

Types of changes

• Tweak (non-breaking change to improve existing functionality)

Checklist:

• My code has been run through clang-format.
• I have read the contributing document.
• My code is not on the master branch.
• The code has been tested.
• All commit messages are properly formatted and commits squashed where appropriate.
• I have included updates to all appropriate documentation.