NSFS | NamespaceFS.js Error handling

[romayalon]

Environment info

• NooBaa Version: 5.17
• Platform: All

Actual behavior

1. Currently, on many NamespaceFS functions we handle/throw all errors the same way, even if they originated from different internal functions and should be treated as internal failures.
2. Most functions have a wrapping try catch and every FS error is translated to S3 error. On some cases this is something we want to avoid.
   For instance - In various cases of calling stat() of internal paths checks, we will throw a non-internal error, like ENOENT - NoSuchObject, which is incorrect. we need to have a correct error handling for each
   In PR we started handling this issue on HEAD object.

Expected behavior

1. Internal issues throwing internal errors.

Steps to reproduce

More information - Screenshots / Logs / Other output