Batch config files need extended validation, make sure all files references within are correct

[darrenmo12309]

• for a batch config, there is 1 treatment yaml file referenced within it and many prompt markdowns. Make sure all of these files are correct so that when an experiment is launched we can be assured that it will run correctly without errors
• Include file checking for batch configs, files must exist in workspace
• Compile any errors for these groups of files into the output console or display all of them in the text editor window