2.0/290 Remove trailing whitespace, dead code. Add tests to check it.

[baseTwo]

ℹ️Work for #290

• Add a test to check that there are no trailing whitespace in the code files.
• Fixed the files where that was case
• Removed files in dead folder

Failing test looks like this

The following files have lines with trailing whitespace:
\Demo\CLI\LibraryRunner.cs
   6:        private readonly StreamWriter? _writer;     <eol>
   6:        <eol>
   6:                    <eol>
   6:        #region Writing Output     <eol>
   6:    }   <eol>
\Cql\Cql.Compiler\Expressions\NullConditionalMemberExpression.cs
   6:            // Nothing <eol>
\Demo\CLI\Helpers\ResourceHelper.cs
   6:        };     <eol>
   6:            parametersConverted.Add(parameter.Name, converted!);         <eol>

[baseTwo]

When running tests on the build pipeline, the tests are isolated from the source code, so it is not possible to get access to the solution dir from the test runner agent. The PR is therefore closed