yuzu: Add settings reset button to general configuration

Builds on german77's work to reset all settings back to their defaults.
This include UISettings and Settings values structs, but does not affect
save profiles, input profiles, and game directories.

This works from a button input in configure_general. When activated, it
calls a callback to close the whole configure dialog, then GMainWindow
deletes the old configuration, both on disk and in memory, and
reinitalizes a new one. It also resets a portion of the UI and calls the
telemetry window prompt.