Support simple RBAC in the wallet proxy

[limemloh]

Purpose

Support simple RBAC in the wallet proxy closes COR-2230
Depends on Concordium/concordium-client#415

Changes

• Update concordium-client
• Support computing cost for new RBAC token operations.

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.