Refactor to help integrate proposer in staging

[druiz0992]

Changes to help integrate new proposer in staging/prod. It shouldn't have any effect on dev:

• includes new proposer endpoint to access contracts from proposer
• add deployment env vars to config
• deploy mock tokens enable
• goerli config
• Adapts to changes in config/default.js from feat: adding a restriction to proposers and challenger 🤌 #550

To test changes on dev, run ping-pong test.

Closes #576

[druiz0992]

There has been some changes requested by @IlyasRidhuan to include an endpoint to get contract addresses from the proposer for the wallet. I will add these changes on this PR.

Outdated because of new code

[ChaitanyaKonda]

If Nf3Instance is a wrapper around SDK calls, then we should be consistent and use this for the following lines too

• await nf3.init(undefined, 'optimist');
• await nf3.registerProposer(environment.proposerBaseUrl);

If not, we can remove Nf3Instance wrapper entirely and use nf3 from const nf3 = new Nf3(signingKeys.proposer1, environment); for all the calls to SDK too.

[druiz0992]

The idea of this wrapper was to store a copy of the nf3 instance so that functions in route modules could access it. I did not intended it to be a real wrapper. But I followed your recommendation and encapsulated all functions. Done

[ChaitanyaKonda]

Changes requested