Make TNT sulfur cubes less destructive

Current TNT sulfur cubes do not fit minigames due to its damage and destructiveness.

Please let their explosion not break blocks or cause damage by default. But they should knockback and ignites others still.

If a TNT sulfur cube is ignited and then sheared, it will regain damage and destructiveness as regular TNTs. 

When ignited through an explosion, if the explosion is destructive, the TNT sulfur cube will also be destructive, and vice versa.