Handle unhandled exceptions in compiler

[adamconnelly]

Add a general exception handler to the compiler that directs users to GitHub to report an issue. If an exception is thrown and not handled by the application, it's probably fair enough to say it's a bug that should be fixed.

• Add a general exception handler to the compiler console app.
• Create a bug issue template and get the exception handler to output a link to report a bug.
• Could we add something to allow users to automatically create an issue / pre-populate some of the details?

Maybe we output something like this:

<start of stacktrace>
  at Antlr4.StringTemplate.Interpreter.Execute(ITemplateWriter out, TemplateFrame frame)
  at Antlr4.StringTemplate.Interpreter.Execute(ITemplateWriter out, TemplateFrame frame)

Thrift.Net has encountered an error. This is a problem with the compiler and not caused by your code.
Please help us to resolve this by reporting a new issue here: <https://github.com/...>.

We welcome contributions, so please feel free to create a PR to resolve the issue.
You can find out how to contribute here: <link to contribution guide>.

Resources:

• https://docs.github.com/en/free-pro-team@latest/github/managing-your-work-on-github/about-automation-for-issues-and-pull-requests-with-query-parameters