NFS exports file import fails if there is more than a space after share path

[ttufts]

Bug Info

Describe the bug
exports file format supports unlimited whitespace between share name and options. When importing an exports file into cockpit, there is an error if there is more than a single space between parts of each line.

To Reproduce
Steps to reproduce the behavior:

1. Create an exports file with multiple spaces between the mnt path and the options
2. Attempt to import the exports file
3. See error

Expected behavior
Properly parse exports file according to man page

Screenshots
If applicable, add screenshots to help explain your problem.

Client Side

Desktop (please complete the following information):

• OS: MacOS Sonoma
• Browser: Brave
• Version Version 1.67.134 Chromium: 126.0.6478.186 (Official Build) (arm64)

Server Side

• OS: Debian 12 Privileged LXC running on Proxmox
• Cockpit Version: 287.1-0+deb12u2