UX improvements

 - app: add dummy client/README.md
 - model: prompt for the model name
 - datasource: prompt for the datasource name
 - model: show connector names in list of datasources
 - property: support typed array
 - model: ask for the plural form
 - acl: remove "property" from the list of scopes

/to @ritch please review
/to @raymondfeng please check that that the array type produced by the generator is valid. Example:
```json
{
  "listProperty": {
    "type": "[string]"
  }
}
```
I prefer to leave trailing comma in place in order to prevent changes on unrelated lines. It's perfectly valid in javascript.