Move Staking UI to Redux + SDK (Kwenta#1674)

* Some contracts and types

* Add these

* Maybe work?

* It actually works

* Remove rewards from getClaimableRewards return

* Perf things

* Fix small issues

* Use vestEnabled

* Remove anonymous functions in EscrowTable

* Restructure SDK functions

* Add approve default

* Switch to using BigNumber amounts

* Fix types

* Handle disabling buttons when action is loading

* Add multicall things

* Remove unused useGetFiles hook

* Make wei changes

* Remove unused import

* Replace ethers.BigNumber with BigNumber

* Small performance improvement

* More small optimizations

* Remove redundant async annotation

* Add consideration to README

* Some fixes

* Disable claim when totalRewards is zero

* Fix unstake for LP tokens

* Fix ABI issue

* Claimable rewards