Multi-chain support (EVM chains)

[elpiel]

See AmbireTech/adex-validator#324 for more details
Chain IDs: https://chainid.network/

When working with Channels we need to try and map the known addresses of stablecoins to the passed Channel.token and "guess" the chain on which this channel is located (ethereum, polygon, etc).

✅ Configuration

Configuration should allow for setting up allowed tokens (and chains). So configuration for allowed tokens and chains is explicit and we have to specify the chain id and address.
Each Chain should also have the addresses of the OUTPACE & Sweeper contracts

✅ Adapter

1. RPC

The information about the Chain will be then used to initialize the Adapter with the correct rpc url for this chain.

2. Authentication token

Chain will be used to generate to Authentication token as well, since we need this information, when we're calling the Adapter::session_from_token. This is the case, because of #452 which uses the Identity contract (on a given chain) if the payload contains an identity address

Sentry

All calls should be filtered out based on the Authentication token Chain, otherwise the identity as which we've authenticated as in the given chain, won't be valid for other chain's records (like channels, campaigns, analytics, etc)

[elpiel]

Any outstanding changes regarding the multi-chain support can be handled separately.