library/util_axis_fifo_asym: Updated IP

[IstvanZsSzekely]

PR Description

Updated IP parameterization and documentation.

Current Asymmetric FIFO parameters make it difficult to understand and properly parameterize the core.
Simplified the core parameters, while maintaining all functionality that was present up until this point.
Updated the documentation as well as the testbench, which can be found here.

PR Type

• Bug fix (change that fixes an issue)
• New feature (change that adds new functionality)
• Breaking change (has dependencies in other repos or will cause CI to fail)
• Documentation

PR Checklist

• I have followed the code style guidelines
• I have performed a self-review of changes
• I have compiled all hdl projects and libraries affected by this PR
• I have tested in hardware affected projects, at least on relevant boards
• I have commented my code, at least hard-to-understand parts
• I have signed off all commits from this PR
• I have updated the documentation (wiki pages, ReadMe files, Copyright etc)
• I have not introduced new Warnings/Critical Warnings on compilation
• I have added new hdl testbenches or updated existing ones