Create library for connecting wallets to Joystream webapps

Part of #5010

I think Atlas and Pioneer currently use 2 separate libraries to manage wallet connections. This will be painful so I propose we build one shared library for any app to connect to Joystream. This will be a great start to SDK in the future but let's keep it simple for now and ship.

It's not worth implementing and maintaining all of the wallet logic ourselves. I did a small WalletConnect MVP with [paritytech/polkadot-onboard](https://github.com/paritytech/polkadot-onboard) and it worked well but not all functionality is available because of hardcoded Polkadot ID https://github.com/paritytech/polkadot-onboard/issues/167. We could fork it or patch it to replace that with Joystream ID. Alternatively, we could use something like Talisman Connect for regular wallets and build our own WalletConnect logic ([docs.walletconnect.com/advanced/multichain/polkadot/dapp-integration-guide](https://docs.walletconnect.com/advanced/multichain/polkadot/dapp-integration-guide)), but not sure if that's worth it. Maybe there are other Substrate libraries?