Verify a schema as a Mermaid diagram in markdown, svg or png

[SimonCropp]

Adds support for verifying the tables of a schema as a Mermaid ER diagram, using DbToMermaid.

await Verify(connection)
    .SchemaAsDiagram(
        DiagramFormat.Markdown |
        DiagramFormat.Svg |
        DiagramFormat.Png);

• SchemaAsDiagram selects markdown, svg, png, or any combination. One file is verified per format. Defaults to markdown.
• Only available on net10.0, since SqlServerToMermaid and Naiad only target net10.0. The other targets are unchanged.
• SchemaIncludes and SchemaFilter do not apply to a diagram. All tables are included.
• Adds a net10.0 dependency on SqlServerToMermaid, which brings in Naiad for svg and png rendering. Naiad's sponsorship build check flows to consuming projects.
• Adds the Papyrine OpenSource exemption to Directory.Build.props.
• Bumps the version to 12.3.0.