Bringing Amex Tokenization to live

[Pranen]

In this pull request, i added the QA-Env, correct versions for the build and if you add your credentials, the amex tokenization should also work.

[CLAassistant]

Thank you for your submission! We really appreciate it. Like many open source projects, we ask that you all sign our Contributor License Agreement before we can accept your contribution.
1 out of 2 committers have signed the CLA.

✅ Pranen
❌ pbrantsc
_{You have signed the CLA already but the status is still pending? Let us recheck it.}

[Sunny-Hirani]

@Pranen - Thank you for the proposed changes, Could you remove the main method in AmexTokenizationClient.java and commented code ?