override default ports in project.json

[akelch]

allow something like this:

`{
"cli-version": "2.0.1",

"default": {

    "port": 8085,
    "gunicorn_port":8091,

    "application_name": "project",
    "builds": {
        "admin": {
            "command": "viur package install admin",
            "kind": "exec",
            "version": "4.5.5"
        }
    },
    "distribution_folder": "./deploy",
    "sources_folder": "./sources",
    "version": "trail-dev"
},
"develop": {
    "application_name": "project",
    "version": dev"
},
"format": "2.0.0"

}`

this is the command: viur run develop --port=8085 --gunicorn_port=8091