[HOB] Implement Gandalf, Goblins' Bane

[N3utrn0]

Implements Gandalf, Goblins' Bane // Flameshape from HOB.

Locally compiled and tested:

• Casting Gandalf normally
• Noncreature spell trigger
• Multiple noncreature spell triggers
• Adventure casting
• Exiling the top two cards face down
• Playing exiled spells while controlling a Wizard
• Playing exiled lands while controlling a Wizard
• Losing the last controlled Wizard correctly prevents playing the exiled cards
• Controlling a Wizard again correctly allows the exiled cards to be played again

The implementation was tested locally using an XMage client and server.