refactor(Logger): use trace log level by default
refactor(Logger): use trace log level by default

When adding the Logger script to the scene to customize its settings the
log level was initially set to `Info` by default, despite the
automatically created Logger using `Trace` instead.
This change makes sure `Trace` is used in all cases by default and
simplifies the automatic creation to use the default values.

red-horizon/VRTK,mattboy64/SteamVR_Unity_Toolkit,Fulby/VRTK,virror/VRTK,thestonefox/SteamVR_Unity_Toolkit,Innoactive/IA-unity-VR-toolkit-VRTK,gpvigano/VRTK,gomez-addams/SteamVR_Unity_Toolkit,gpvigano/SteamVR_Unity_Toolkit,thestonefox/VRTK,adamjweaver/VRTK,TMaloteaux/SteamVR_Unity_Toolkit