Add `std::formatter` for `std::exception` that extracts boost annotations.

[tarek-y-ismail]

[non blocking] We should probably create a formatter for std::exception that tries to extract the boost annotations

Originally posted by @AlanGriffiths in #5133 (comment)

[tarek-y-ismail]

@AlanGriffiths Mind providing some more context on this? I'm not very familiar with boost exceptions.

[AlanGriffiths]

The existing, iostream based, implementation is here:

mir/src/core/report_exception.cpp

Lines 24 to 56 in 0cc56e8

	void mir::report_exception(std::ostream& out_stream, std::ostream& err_stream)
	{
	try
	{
	throw;
	}
	catch (ExitWithOutput const& output)
	{
	out_stream << output.what() << std::endl;
	}
	catch (AbnormalExit const& error)
	{
	err_stream << error.what() << std::endl;
	}
	catch (std::exception const& error)
	{
	// First report any nested exceptions
	try
	{
	std::rethrow_if_nested(error);
	}
	catch(...)
	{
	report_exception(out_stream, err_stream);
	}
	err_stream << "ERROR: " << boost::diagnostic_information(error) << std::endl;
	}
	catch (...)
	{
	err_stream << "ERROR: unrecognised exception. (This is weird!)" << std::endl;
	}
	}