Add cross-chain adapter contracts for Story L1

[Spablob]

Why

Cross-chain adapter contracts are required to achieve decentralized bridging from ETH mainnet to Story L1 mainnet.

How

UMA team has shared technical documentation with guidance on what needs to be built and how.

Resolution

As confirmed with UMA team - the output of this PR is the creation of 2 new smart contracts:

• Story_ChildMessenger.sol
• Story_ParentMessenger.sol

These should be added to the folder:
https://github.com/UMAprotocol/protocol/tree/master/packages/core/contracts/cross-chain-oracle/chain-adapters

Difficulty Score [1-10]

UMA team shared the technical requirements and will review the PR.