Support new GRPC endpoints

[td202]

Purpose

Closes #331
Depends on: Concordium/concordium-base#578

This adds support for the new GRPC queries GetScheduledReleaseAccounts, GetCooldownAccounts, GetPreCooldownAccounts, and GetPrePreCooldownAccounts as raw commands. Additionally, it supports the parameter field in ContractInitialized transaction events.

Changes

• Use SupplementedEvent, SupplementedTransactionStatus, SupplementedTransactionSummary and SupplementedValidResult in place of the non-supplemented versions.
• Decode the parameter field in ContractInitialized events.
• Add gRPC wrappers and raw commands for:
  • GetScheduledReleaseAccounts
  • GetCooldownAccounts
  • GetPreCooldownAccounts
  • GetPrePreCooldownAccounts

Checklist

• My code follows the style of this project.
• The code compiles without warnings.
• I have performed a self-review of the changes.
• I have documented my code, in particular the intent of the
  hard-to-understand areas.
• (If necessary) I have updated the CHANGELOG.

[drsk0]

lgtm