Where a power to sell lands is given in any mortgage, the power is part of the security and may be executed by any person, or the personal representative of any person who, by assignment or otherwise, becomes entitled to the money thus secured. A conveyance of the lands sold under such power of sale to the purchaser at the sale may be executed by the mortgagee, their agents, attorneys or any person making the sale. Such conveyance vests the legal title of the lands sold under the power of sale to the purchaser at the sale. Probate judges shall index foreclosure deeds by the name of the original grantor and grantee in the mortgage, deed of trust, or other conveyance intended to secure the payment of money, and also by the names of the grantor and grantee in the foreclosure deed.