Tokenomics + Handling API keys as secrets

[imadarchid]

This PR introduces several changes to ensure that MADT is able to honor redemptions in case of fluctuations in the USD/MAD rate. It also introduces a sample API request to two providers for the DON to execute.

Changes

• Rebase mechanism that inflates/deflates the supply.
• API request to Exchangerate API and CurrencyAPI. Other providers can be added and a median rate can be taken in consideration.
• Adding a deployAll script to enhance the dev UX.

[imadarchid]

To-do:

• Write the request to retrieve exchange rates + test it locally.
• Include fee structure for oracle payment.
• Set up rebasing mechanism (inflate supply when MAD appreciates versus dollar, depreciate otherwise).

[imadarchid]

Fee structure will be determined after I do some txs on testnet.