Switch from `rinkeby` to `sepolia`

[nieznanysprawiciel]

Why:

• rinkeby will be deprecated

What:

• [ ] Add sepolia option to golemsp and payment module
• [ ] Print deprecation message when user explicitly tries to use rinkeby
• [ ] golemsp testnet group should contain sepolia instead of rinkeby
• [ ] Setup faucet (Check if code in our repository will work for sepolia)
• [ ] Deploy contracts on testnet

[nieznanysprawiciel]

This task depends on @golemfactory/devops team

[nieznanysprawiciel]

It seems sepolia won't be our main migration target

[approxit]

@nieznanysprawiciel If not sepolia, which one will be chosen (assuming that rinkeby will still be shut down in Q2-Q3 2023)?