Updating DataTables Source Files: Addressing Website Changes and File Inconsistencies

The process for updating DataTables source files has changed due to modifications on the DataTables.net website. The site no longer provides zip files for download, and the file content differs from previous versions. Consequently, the entire update process requires revision. I have implemented the tools/downloaded_src_files.R script, which can download similar source files from the DataTables.net website. However, more time and effort are needed to fix the update_DT.R script. Several issues have been observed: - Many CSS files are missing from the new downloads. - There are inconsistencies in the file structure and content. - While the minification issue has been addressed, some non-minified files still exist (this problem has been resolved). Further investigation and development are necessary to fully adapt our update process to these changes and ensure all required files are properly downloaded and integrated. fixes #1141