Improve contracts for reference node

[guidanoli]

This issue aims to consolidate all changes proposed to improve the reference node. Currently, the contracts either do not provide the full information necessary for the node to catch up with PRT disputes, or the code is not ideally laid out for binding generation.

• Ensure event names are in PascalCase
• Ensure event parameters are named
• Add matchId parameter to match creation event
• Add finalState and sender parameters to commitment joining event
• Emit commitment joining event before match creation event
• Move events, errors, and functions definitions to proper interfaces
• Remove left and right node parameters from joinTournament function
• Add reason parameter to match deletion event
• Expose tournament arguments through view functions
• Use either levels or maxLevel consistently

[GCdePaula]

We should also expose the arbitration constants!

[guidanoli]

In PRT v2, we left some items unaddressed.
Let's try tackling them for the next release?
@GCdePaula @stephenctw @pedroargento @ZzzzHui @henriquemarlon