[FEATURE] Document Store can load files but not folders

[chrisbriend]

The UI doesn't let you select multiple files, or a folder when using the File Loader in the Document Store tab of the app.
Even though the icon show multiple files,.

In the Chat Flow UI, there is a separate "Folder With Files" loader, but it's not accessible from the document store - it seems both kind of document loaders are implemented in different places in code.
It also seems that the file loader "File.js" already almost supports folder, as it supports handling an array of files..

[HenryHengZJ]

You can upload multiple files:

[chrisbriend]

Not sustainable if you have a folder with 100s of files though, Why does it not let me select a folder?