Use XDocument to do XML operations when generating web.config

[ChengTian]

parent #778

@davidfowl , XmlReader.Create on CoreCLR always throws exception

System.Xml.XmlException: An internal error has occurred.
   at System.Xml.XmlXapResolver.GetEntity(Uri absoluteUri, String role, Type ofObjectToReturn)
   at System.Xml.XmlTextReaderImpl.FinishInitUriString()
   at System.Xml.XmlTextReaderImpl..ctor(String uriStr, XmlReaderSettings settings, XmlParserContext context, XmlResolver uriResolver)
   at System.Xml.XmlReaderSettings.CreateReader(String inputUri, XmlParserContext inputContext)
   at System.Xml.XmlReader.Create(String inputUri, XmlReaderSettings settings, XmlParserContext inputContext)
   at System.Xml.XmlReader.Create(String inputUri)
   at ConsoleApp3.Program.Main(String[] args) in C:\Users\wwa\Documents\Visual Studio Next\Projects\ConsoleApp3\src\ConsoleApp3\Program.cs:line 15

So I use

XDocument.Parse(File.ReadAllText(webConfigFilePath));

[davidfowl]

Why are we still generating k.ini files? Didn't @GrabYourPitchforks move everything to web.config?

[ChengTian]

This change was approved for Beta. I removed k.ini generation and added functional tests.

@davidfowl @GrabYourPitchforks , please help to review when you have time. Thanks.

[davidfowl]

[GrabYourPitchforks]