MVP

• Change a block's visibility
• Delete a block
• Move a block to another zone
• AddBlockToZone(BlockInput, ZoneId)
• UpdateBlock(BlockId, BlockInput)
• Change a block's position in its zone. Possibilities (need to choose):
• MoveBlockToPosition(3)
• MoveUp(), MoveDown(3)
• MoveBlockBefore(block) / MoveBlockAfter(block)

Later

• switch layout