Plugin loading chain

The plugin initialize itself in a few steps:

1. Plugin loaded by WordPress - all the classes and functions are loaded

2. do_action( 'notification/boot/initial' )

3. On plugins_loaded with priority 10 Carriers, Recipients and Global Merge Tags are loaded

4. On init with priority 1000 Triggers are loaded

5. do_action( 'notification/boot' ) - Plugin is fully initialized and all the defaults are loaded