Add timing functions for hooks

[crstauf]

Been waiting for QM to adopt this functionality since 2019 (johnbillion/query-monitor#309, johnbillion/query-monitor#407), might as well implement here until it shows up there.

add_action( 'init', 'qmx_start', 0 );
add_action( 'init', 'qmx_lap', 5 );
add_action( 'init', 'qmx_stop' );

// Timer runs from `0` to `PHP_INT_MAX` priorites.
add_action( 'template_redirect', 'qmx_auto', 0 );