chore: update migrations to support percetange fee handler + flow improvements

[nmlinaric]

Description

• Update configs across all networks to work with percentage fee handler
• Update setting fee handlers - enable possibility to not set any fee handler
• Add truffle-verify package
• Add all deployed networks to truffle-config

Related Issue Or Context

How Has This Been Tested? Testing details.

manual tests

Types of changes

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to change)
• Documentation

Checklist:

• I have commented my code, particularly in hard-to-understand areas.
• I have ensured that all acceptance criteria (or expected behavior) from issue are met
• I have updated the documentation locally and in chainbridge-docs.
• I have added tests to cover my changes.
• I have ensured that all the checks are passing and green, I've signed the CLA bot