Refactor ovs_offload_lnw_v2.py (example)

[ffoulkes]

Revised ovs_offload_lnw_v2.py to make it easier to read and maintain.

1. Refactored monolithic main program.

   • Extracted command strings to module level.
   • Extracted subcommand processing to individual functions.
   • Implemented validate_host_password() and print_banner() helper functions.

2. Corrected some grammar errors.

   • Corrected prepositional verbs in printed messages and comments (e.g. "Setup" -> "Set up").
   • Fixed comma splices in help text.

3. Did a little reformatting.

   • Ran a Python formatter, whose main effect was to insert spaces before and after plus signs.
   • Wrapped a couple of long comments.