[ADD] Upgrade THORChain ETH Router to v4

Related to #1314 (closed)

THORChain recently hard forked , after hard fork , router has not been upgraded , thus router upgrade controller can be cleaned up , and also update it to for the upcoming router upgrade.

The process to upgrade router will be like the following

1. admin mimir ChurnInterval -> 432000 to avoid churn
2. admin mimir StopFundYggdrasil -> 1 , to stop funding yggdrasil
3. admin mimir StopSolvencyCheckETH -> 1 to stop Solvency checker on ETH chain , to make sure the migration fund will not cause solvency checker to halt the chain
4. admin mimir MimirRecallFund -> 1 , to recall yggdrasil fund
5. Wait for a few minutes , until all yggdrasil vault return all the ERC20 tokens
6. admin mimir MimirUpgradeContract -> 1 to update the router on Yggdrasil vault , make sure router contract has been updated on all yggdrasil vaults
7. admin mimir ChurnInterval -> 43200 , resume churn
8. Wait churn to kick off , and make sure funds have been migrate from older asgard to new ones.
9. Resume StopFundYggdrasil -> 0
10. Resume StopSolvencyCheckETH -> 0 , to start solvency checker on thorchain