Replace Web3J Direct Usage by EthAPI Client

[fluentcrafter]

🔐 🔐 Should this be a security advisory instead? 🔐 🔐

Description

Replace the usage of Web3J by EthAPI client

Motivation

• Code consistency
• Reduce Web3J surface in the code base
• Facilitate upgrades of Web3j Lib
• Improve testabilitt by usage of a Fake ethApi Client