Add packing for dynamic array and slice types (#18051)

* added tests for new abi encoding features (#4)

* added tests from bytes32[][] and string[]

* added offset to other types

* formatting

* Abi/dynamic types (#5)

* Revert "Abi/dynamic types (#5)" (#6)

This reverts commit dabca31d797623d43bd780721fc0ad461d24be53.

* Abi/dynamic types (#7)

* some cleanup

* Apply suggestions from code review

apply suggestions

Co-Authored-By: vedhavyas <vedhavyas.singareddi@gmail.com>

* added better formatting (#8)

* review chnages

* better comments