view: extend view service for auctions

[erwanor]

We want to amend the view service definition to add an Auctions rpc that the transaction planner will be able to use:

service ViewService {
    // ...

    // Gets the auctions controlled by the user's wallet.
    rpc Auctions(AuctionsRequest) returns (stream AuctionsResponse);

    // ...
}

message AuctionsRequest {
    // If present, filter balances to only include the account specified by the `AddressIndex`.
    core.keys.v1.AddressIndex account_filter = 1;
    // If present, include inactive auctions as well as active ones.
    bool include_inactive = 2;
    // If set, query a fullnode for the current state of the auctions.
    bool query_latest_state = 3;
}

message AuctionsResponse {
    core.component.auction.v1.AuctionId id = 1;
    // The note recording the auction NFT.
    SpendableNoteRecord note_record = 4;

    // The state of the returned auction.
    //
    // Only present when `query_latest_state` was provided.
    google.protobuf.Any auction = 2;
    // The state of any DEX positions relevant to the returned auction.
    //
    // Only present when `query_latest_state` was provided.
    // Could be empty, depending on the auction state.
    repeated core.component.dex.v1.Position positions = 3;
}

[TalDerei]

should we wait to close this until a storage impl is filled into the stub?

[erwanor]

@TalDerei Created #4251 to track impl.