Add ER Diagram feature using mermaid

[badsyntax]

Overview

• Use scaffolding with a custom .t4 template to generate the mermaid code, which is then rendered in a custom webview
• Add a new project to generate the webview build
• Use d3 to add zooming features
• Lots of various fixes and improvements

ScreenShots

TODO

• CLR type to DB type & mermaid ER attributes
• Better provider selection using transitive packages
• Maybe don't save the t4 template in the dest project?
• Improve cli args (eg plural names)
• Add tests to check this works in windows Too many bugs in the test framework, eg: ViewItem.getActionButton/s hangs webdriverio-community/wdio-vscode-service#61
• Improve FK names (it can be too noisy)
• Improve cli loading states
• Zoom controls
• Inputs should not close when loosing focus
• Handle closing webview
• Fix svg export
• Fix diagram title (can we use the db name?)