Add Reject Events

[ghost]

Purpose

Adding tables to store events when contract- and module entity interaction fails.
Task

• https://concordium.atlassian.net/browse/CBW-1261

Changes

• Added tables for contract- and module entity rejected events
• Change database import job to use Parallel library, such that runtime itself can optimise worker count
• Added transaction sender to all tables, since this information is often needed in the UI and we then are able to avoid a account lookup through the references transaction.

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.