add sepolia, remove rinkeby, ropsten & kovan

[goosewobbler]

• Add Sepolia to default chains
• Remove Rinkeby, Ropsten & Kovan from default chains
• Remove Goerli RPCs - Mudit, Slockit & Prylabs - Goerli state reset and turned off when a removed RPC is active
• Use eth-provider presets for every chain

[mholtzman]

I think we need to add a migration to add the new network to existing configs as well

[mholtzman]

no, we don't want to delete any

[goosewobbler]

I realised I misread your comment 😅

[mholtzman]

also seems like the tests are failing? (edit: nm see it's a dependency issue)