PoA Network support

[youtweakit]

ETH-Hot-Wallet

Thank you for contributing!

Please open an issue before embarking on any significant pull request, especially those that
add a new library or change existing tests, otherwise you risk spending a lot of time working
on something that might not end up being merged into the project.

Before opening a pull request, please ensure:

• double-check your branch is based on dev and targets dev
• Pull request has tests (we are going for 100% coverage!)
• Code is well-commented, linted and follows project conventions
• Documentation is updated (if necessary)
• Internal code generators and templates are updated (if necessary)
• Description explains the issue/use-case resolved and auto-closes related issues

Be kind to code reviewers, please try to keep pull requests as small and focused as possible :)

IMPORTANT: By submitting a patch, you agree to allow the project
owners to license your work under the terms of the [MIT License].

[PaulLaux]

Why did you change Infura keys for Ropsten Testnet and Main Net?

[youtweakit]

I've copied my infura keys from another project. Is it important to keep
any of them? )