Bring consistency back to the argspecs and documentation.

There are 3 areas where the documentation and argument structures are used:

• docs directory, which contains the *.rst files for documentation
• plugins/module_utils/network/vyos/argspec, which contains the specifications used by Ansible to understand parameters
• modules, where the DOCUMENTATION, RETURN, and EXAMPLES are maintained for use in most of these locations

Historically, these were sourced in another repository which is common to all of the Ansible-maintained collections for network tools using a script to coordinate them. More recently, they're maintained in-tree in the modules directory.

The VyOS sources and derivates have become out of sync with both their original sources and the in-tree versions. The intent here is to bring consistency to the in-tree version to allow us to decide whether to maintain out-of-tree for the older versions or just update from the in-tree.

• Update documentation, specs, and examples to meet current standards
• Fix version_added to comport with current standard (when added to collection)
• Update README with information on how to appropriately regenerate