4.5.2/8.0.12

Differences from upstream:

• Built with .NET Framework 4.5.2.
• Bumps MySQL Connector/NET to 8.0.12.
• Adds class to enable executing procedures asynchronously (thanks w4rgo).
• Changes the delimiter to split procedure parameters from comma , to pipe | to support arrays, e.g. JSON.
• Removes indefinite connection retries to provide output that can be conditioned when querying (e.g. health check).