Add Tabular Diff for CSV files (#14661)

Implements request #14320 The rendering of CSV files does match the diff style.

* Moved CSV logic into base package.

* Added method to create a tabular diff.

* Added CSV compare context.

* Added CSV diff template.

* Use new table style in CSV markup.

* Added file size limit for CSV rendering.

* Display CSV parser errors in diff.

* Lazy read single file.

* Lazy read rows for full diff.

* Added unit tests for various CSV changes.

docs/content/doc/advanced/config-cheat-sheet.en-us.md

@@ -198,6 +198,10 @@ Values containing `#` or `;` must be quoted using `` ` `` or `"""`.
 
 - `ENABLE_RENDER`: **true**: Whether to render SVG files as images.  If SVG rendering is disabled, SVG files are displayed as text and cannot be embedded in markdown files as images.
 
+### UI - CSV Files (`ui.csv`)
+
+- `MAX_FILE_SIZE`: **524288** (512kb): Maximum allowed file size in bytes to render CSV files as table. (Set to 0 for no limit).
+
 ## Markdown (`markdown`)
 
 - `ENABLE_HARD_LINE_BREAK_IN_COMMENTS`: **true**: Render soft line breaks as hard line breaks in comments, which