introduce DeliverMax alias in Payment transactions

[ckeshava]

High Level Overview of Change

This is a sister PR of the following xrpl-py work: https://github.com/XRPLF/xrpl-py/pull/684

Context of Change

Type of Change

• [ ] Bug fix (non-breaking change which fixes an issue)
• [x] New feature (non-breaking change which adds functionality)
• [ ] Breaking change (fix or feature that would cause existing functionality to not work as expected)
• [ ] Refactor (non-breaking change that only restructures code)
• [x] Tests (You added tests for code that already exists, or your new feature included in this PR)
• [ ] Documentation Updates
• [ ] Release

Did you update HISTORY.md?

• [x] Yes
• [ ] No, this change does not impact library users

Test Plan

Unit tests have been added, but I am unable to add integration tests. I couldn't find any examples of specifying a JSON representation (not Payment, AccountSet or any SubmittableTransaction type) as an input to the submitTransaction function. This is necessary because DeliverMax is an alias at the RPC level, it is not recognised at the protocol level. Let me know if I'm missing something.

[khancode]

Closing this since the other solution was merged in - https://github.com/XRPLF/xrpl.js/pull/2689