Ignore private files.

[danepowell]

When creating a new project with BLT following these instructions, after the local:setup step I get a /files-private directory in the repo root that should be gitignored.

I'm not quite sure why this directory is created in the repo root instead of in the Drupal docroot. This PR seems like it would put it into the docroot: #322 🤷‍♂️

Regardless, I'm definitely not seeing it at docroot/sites/*/files-private, which is where BLT apparently expects it to be following #732, so I figure we should change to the gitignore to match reality.

@dpagini under what circumstances were you seeing files show up at docroot/sites/*/files-private? I'm guessing it was for an older version of BLT?

[dpagini]

I think I was operating off an incorrect assumption, actually. This was because the default.local.settings.php file sets the private directory locally. Since the gitignore already had the entry for docroot/sites/*/private, I was thinking this meant the expected place for local private files was that directory.
This makes more sense to me... but then I just wonder what that entry for docroot/sites/*/private is for at all?

[dpagini]

I see this was already merged... but had an after thought... With this setup, you are likely to have only one private files directory for all sites. I don't think multi-site support is fully fleshed out at this point in time, but should the directory be something more like:

$settings['file_private_path'] = $dir . "/files-private/$site_dir"

This would follow more closely the setup of the config/ directory, I think.

If you guys agree I could post a PR with that or create an issue to discuss further. LMK.

cc: @danepowell @grasmash