CSCD-9215: Improvements to the migration tool:
- Speeded up skipping of existing assets
- Avoiding running jTidy if content doesn't have a single root
- Stripping doctype before validating XML to speed up the validation
- Clearing the root level folders and migraiton status when mapping is loaded to avoid issues when one migration has run and user is starting another one
- If a file fails to get created, it will be counted in the "Errors" section
- If a folder name has an illegal character, that character is stripped and a root level folder assignment is created to rewrite all the links that link to assets in that folder to have updated folder name
- If a file name has an illegal character, that file will not get imported
- Fixed an issue where during folder creating if folder's parent folder was root folder, it was trying to use empty string as parent folder path and failing to create that folder. Using "/" as parent folder path now.
- Avoiding logging statements informaing about invalid XML when checking if XML is valid
- Fixed outputting the XPath results so that it handles all types of XML nodes
- Enlarged the XPath input field in the UI
- Fixed escaping of the XPath so that double quotes can be entered and work fine