feat(dup): rename change_dup_status to modify_dup

[neverchanje]

This PR renames "change_dup_status" to "modify_dup".

I need an API to dynamically change some behavior of the duplication, like "app_env" changing the behavior of an app. Since an app may have multiple duplications, this feature cannot be implemented by "app_env".

So I want to reuse the "change_dup_status" API that not only "status" can be changed, but also the new attribute. "modify_dup" is surely more extensible:

struct duplication_modify_request
{
    1:string                    app_name;
    2:i32                       dupid;

    // status is optional. Because modification of a dup may leave the status unchanged.
    3:optional duplication_status status;

    /// new attribute
    4:optional bool xxx.
}