Apply several fixes to NFS service

[igorpecovnik]

Description

• splitting client and server into separate modules
• move client discovery to run_time
• install nmap package if this module is used so we don't need to add this to dependency

Include fixes from #312

Testing Procedure

• Install / remove
• Enabling server, export folder, mount from remote
• Discover servers in subnet, mounting to share

Checklist

• My code follows the style guidelines of this project
• I have performed a self-review of my code
• I have ensured that my changes do not introduce new warnings or errors
• No new external dependencies are included
• Changes have been tested and verified
• I have included necessary metadata in the code, including associative arrays