adding marketplace

[MartianSiddharth]

Motivation

Writing the first Marketplace contract for Aptos. This is based on the TODO item of this issue.

The implementation is based on TokenTransfers.move.

The flow is:

1. Market Owner initiates the marketplace, all the tokens will be escrowed using this account
2. Seller lists the token for sale
3. Buyer buys the token using the token id: this includes sending the listing fees to the market owner and buying price to the seller of the token.

The only rule of the marketplace is that the buyer cannot be the seller.

When a token is listed for sale, the token is escrowed to the market owner account. When a buyer buys the token, the token is claimed by the buyer and removed from escrow from the owner account.

(Write your motivation for proposed changes here.)

Have you read the Contributing Guidelines on pull requests?

Yes

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Test Plan

Added a test for the move module as the function (list_buy_test).
Also, tested the script by publishing it and testing the functions.

[davidiw]

I think this PR has been superseded, so will focus over there :)