streamflow: Confluence testnet deployment updates

[yondonfu]

What does this pull request do? Explain your changes. (required)

This PR contains:

• Various updates to deployment scripts to allow them to run smoothly
• Add Hardhat tasks for common contract interactions: unpause, set-contract-info, register-gateway-with-router, set-round-length
• Add a DummyGateway that was used for testing register-gateway-with-router on Rinkeby
• Add Arbitrum helpers from https://github.com/makerdao/arbitrum-dai-bridge
• A Rinkeby deployment for Confluence testnet phase 1
• A BondingManager update to avoid extra computation in pendingStake()/pendingFees() for an unstaked address
• An update to the Rinkeby deployment for a BondingManager upgrade

Sorry for the big PR! Ended up doing all these things as a part of the Confluence testnet phase 1 deployment on Rinkeby.

We'll likely cherry pick a bunch of these commits into confluence as well since they will be helpful for running deployments of the contracts to L2 off that branch.

Reviewing this PR should be easier if you review commit by commit and first skip the following commits:

• https://github.com/livepeer/protocol/pull/525/commits/9b6af60045d1a63f928d41bf6dd7867113ffe7e3 which runs prettier on additional files
• https://github.com/livepeer/protocol/pull/525/commits/f076fa59fdc1a3f1b8e9a2247d1509ab080134ce which adds a bunch of Rinkeby deployment files

since these two commits change many files.

Specific updates (required)

See commit history.

How did you test each of these updates (required)

Does this pull request close any open issues?

Checklist:

• [ ] README and other documentation updated
• [ ] All tests using yarn test pass

[coveralls]

Pull Request Test Coverage Report for Build 1820419313

• 3 of 3 (100.0%) changed or added relevant lines in 1 file are covered.
• No unchanged relevant lines lost coverage.
• Overall coverage increased (+0.004%) to 98.63%

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Totals
Change from base Build 1814506002:	0.004%
Covered Lines:	895
Relevant Lines:	906

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💛 - Coveralls

[yondonfu]

All commits except for 6086b59 and 13713ba were already merged into confluence and I recommend just lightly reviewing these commits because these changes were only needed for the L1 BondingManager for testnet and are not applicable for mainnet since we will not be updating the L1 BondingManager on mainnet.