Assigning something to `process.env.profile`, Node stringifies the value. This
means that assigning `undefined` to an environment variable in Node will result
in it holding the string `undefined`.
This means, for example, that `module.exports.FFPROBE_PATH || 'ffprobe'` in
`server/libs/nodeFfprobe/index.js` will actually result in the string
`undefined`.
This patch fixes several such assignments in the `index.js`, potentially
causing problems in the development mode.
If the scanner detects new files with a path containing part of the name
of an already existing library item, the new item will incorrectly be
detected as being a parent directory of the already existing item and
the import will be aborted.
You can follow these steps to reproduce the issue:
```
❯ mkdir audiobooks/author/
❯ mv title\ 10 audiobooks/author
[2022-12-18 22:14:12] DEBUG: [Watcher] File Added /home/lars/dev/audiobookshelf/audiobooks/author/title 10/dictaphone.mp3
[2022-12-18 22:14:16] DEBUG: [DB] Library Items inserted 1
❯ mv title\ 1 audiobooks/author
[2022-12-18 22:15:03] DEBUG: [Watcher] File Added /home/lars/dev/audiobookshelf/audiobooks/author/title 1/dictaphone.mp3
[2022-12-18 22:15:07] WARN: [Scanner] Files were modified in a parent directory of a library item "title 10" - ignoring
```
Since `'title 10'.startsWith('title 1')` is `true`, the current code
makes this false assumption.
This patch fixes the issue by requiring a path separator to be part of
the matching path. This should ensure that only true parent directories
are detected.
This patch requires audiobookshelf to always use Unix file separators.
But that shouldn't be a problem since audiobookshelf always seems to use
these kinds of separators. Even on Windows.
