ICTT Course: Wrap SendAndCall chapter up

[martineckardt]

• The SendAndCall chapters use some of the environment variables we've set in previous chapter. Replace SUBNET for these and make sure the name matches with what we've changed it to
• The Starter kit does not include the the Code examples for DexERC20Wrapper.sol, IUniswapFactory.sol, IUniswapPair.sol and IWAVAX.sol in the main branch yet. The PR is merge into a different branch, but we need to rethink the structure and update all instructions in the academy after. I think just putting them somewhere in the current main branch for now will be easier
• Feel free to add any instructions / background information that a dev could use
• Once merged, let's push this out to the community via X giving Sarp a shoutout

Resources:

• Mock Contracts in ICTT Repo
• PR for code referenced in the assignements. It was merged, but not in main