Add functionality to ignore certain url paths or files

[XThomasBU]

All the child urls are read, processed and stored in the vectorestore, build functionality to ignore certain url paths or files, for example: defined in storage/data/to_ignore.txt

https://github.com/DL4DS/dl4ds_tutor/blob/e934b90b1d5e9771ed279e085200b30c83c29d60/code/modules/vectorstore/store_manager.py#L49

[Farid-Karimli]

@XThomasBU I think this is appropriate for the vectorstore UI - interactively pick links.