RFC0027 CLI command "update-route" to manage generic per-route options

[Dariquest]

CLI Support for Generic Per-Route Options

Introducing a new cli command 'update-route', which allows updates to route resources.
Extending the API of the Route to contain generic options map.

Detailed specification including that of for all the involved components is provided in the RFC

$ cf update-route -h
NAME:
   update-route - Update an existing route.

USAGE:
   cf update-route DOMAIN [--hostname HOSTNAME] [--path PATH] [--option OPTION=VALUE] [--remove-option OPTION]

EXAMPLES:
   cf update-route example.com -o loadbalancing=round-robin
   cf update-route example.com -o loadbalancing=least-connection
   cf update-route example.com -r loadbalancing

OPTIONS:
   --hostname, -n      Hostname for the HTTP route (required for shared domains)
   --path              Path for the HTTP route
   --option -o         Set the value of a per-route option, key-value pairs, repeat to set multiple options
   --remove-option -r  Unset a previously set option

SEE ALSO:
   create-route, map-route, routes, unmap-route

It should be possible to provide options in the create-route and map-route commands.

EXAMPLES:
  cf create-route my-space example.com -o loadbalancing=round-robin
  cf map-route my-app example.com -o loadbalancing=least-connection

Why Is This PR Valuable?

Allow users to manage per-route options via the CLI instead of having to talk to the API directly.

Applicable Issues

GitHub Issue

How Urgent Is The Change?

No urgency

[Dariquest]

Replacing by the #3338 into the appropriate CF CLI version V8 branch