confgenerator: add NFS path detection

[braydonk]

Description

This draft PR shows adding detection to the Ops Agent for NFS include paths in the file receiver. Since NFS does not support inotify, the Ops Agent would detect the include paths from the config and if one of the include paths for that receiver is an NFS directory, it switches that tail plugin to use the fstat backend instead of inotify.

Related issue

b/369376689

How has this been tested?

All testing of this was done manually on a system with an NFS mounted directory. TODO: add an integration test that automates the environment I was using to test this manually.

Checklist:

• Unit tests
  • Unit tests do not apply.
  • Unit tests have been added/modified and passed for this PR.
• Integration tests
  • Integration tests do not apply.
  • Integration tests have been added/modified and passed for this PR.
• Documentation
  • This PR introduces no user visible changes.
  • This PR introduces user visible changes and the corresponding documentation change has been made.
• Minor version bump
  • This PR introduces no new features.
  • This PR introduces new features, and there is a separate PR to bump the minor version since the last release already.
  • This PR bumps the version.