Updates after audit

Added a few minor changes into Registry, Channel and Hermes implementations.

• We don't have ethers on polygon --> clarifying claim function naming
• Emitting event during getStakeBack()
• Operator can only sign promises, all the rest is controlled by "owner" (multisig)
• Improved calculations and moved division to be last operation
• Locked compiler version
• Typos

Exit requests removed

What's Changed

• Mainnet deployment by @chompomonim in #144
• Delete exit request by @chompomonim in #150

Full Changelog: v2.2...v2.3

Mainnet beta

This is version of smart contracts which is going to be deployed for Mainnet beta.

Significant changes from testnet3 contracts:

• adapted contracts for mainnet Polygon realities, use time instead of blocks #133
• fixed couple of minor security fixes #135 #138
• added use of minStake (possibility to require staking) #143
• important hermes actions now will be done by owner, this should decrease operator's keys role and potential attack vector on its keys #140
• identity and pre-image (also called R) is now logged in promise settlement events #132 #136

Mainnet-rc0

Merge pull request #140 from mysteriumnetwork/owner_power

Get use of owner for important hermes settings

Settlement events updated

Merge pull request #132 from mysteriumnetwork/fix/add_r_to_event

added revealed R to events

Initial matic support

Merge pull request #129 from mysteriumnetwork/feature/pay_and_settle

Feature/pay and settle

Final version of Testnet2 smart contracts

• Make settlement twice cheaper
• Beneficiary address is stored in Registry instead of separate hermeses
• There are no stake-goal which simplifies all the flow.

Chain ID added

Merge pull request #123 from mysteriumnetwork/feature/multichain

Added chainID into Promises and all related places

Fixes after code review

• Prevent change funds destination by cheque signed message replay on other channels of the same operator (owned by same identity).
• Prevent replay of updateHermesURL in Registry.
• Deleted ownership denounce functionality. It is not needed in our case.

BetaNet release candidate

• some code cleanup
• don't need to pass nonce as param
• fast withdrawal support