Introduce Battle Action for new arena service

[Atralupus]

From planetarium/ArenaService#19

The action will be a simplified version of the existing BattleArena, removing elements like ticket management, win/loss records, and score tracking. Instead, it will focus solely on executing battles and recording the results in the state.

Additionally, it should include a metadata argument to verify the intent of the battle request by various services.

Proposed Action Parameters

public Address myAvatarAddress;
public Address enemyAvatarAddress;
public string metadata;

• metadata: Services requesting the battle will sign the desired data and send it as a hashed string to be recorded on the chain. This works similarly to a JWT.
• Since only the hash will be stored, this approach seems secure, but a thorough review is needed to ensure it doesn't compromise blockchain security.

Proposed State Format

public class BattleLog : IState
{
    public Address Challenger;
    public Address Opponent;
    public string Metadata;
    public bool IsVictory;
}

This structure is expected to record battle results.

Each service (e.g., Planetarium's ArenaService, another service) should be able to store AccountAddress differently, ensuring flexibility and customization across services.