Add support for Enum Query parameters

[sashirestela]

For example, a function declared like this:

@GET("/someResource")
<ResponseType> someFunction(@Query("enumParameter") Status enumParameter);

enum Status {
    @JsonProperty("open")
    OPEN,

    @JsonProperty("in_progress")
    IN_PROGRESS,

    @JsonProperty("completed")
    COMPLETED;
}

What is invoqued with the following values:

var result = someFunction(Status.OPEN);

Its url should be resolved as:

/someResource?enumParameter=open