feat: add video details response model

- add paginator, impl for playlist items
- small model refactor
- add ignore_any deserializer
- removed unnecessary clones in response mapping

src/model/paginator.rs

@@ -0,0 +1,54 @@
+use serde::{Deserialize, Serialize};
+
+
+/// The paginator is a wrapper around a list of items that are fetched
+/// in pages from the YouTube API (e.g. playlist items,
+/// video recommendations or comments).
+#[derive(Debug, Clone, Serialize, Deserialize)]
+pub struct Paginator<T> {
+    /*
+    /// Total number of items if finite and known.
+    ///
+    /// Note that this number may not be 100% accurate, as this is the
+    /// number returned by the YouTube API at the initial fetch.
+    ///
+    /// It is intended to be shown to the user (e.g. 1261 comments,
+    /// 18 Videos) and for progress estimation.
+    ///
+    /// Don't use this number to check if all items were fetched or for
+    /// iterating over the items.
+    pub count: Option<u32>,
+    */
+    /// Content of the paginator
+    pub items: Vec<T>,
+    /// The continuation token is passed to the YouTube API to fetch
+    /// more items.
+    ///
+    /// If it is None, it means that no more items can be fetched.
+    pub ctoken: Option<String>,
+}
+
+impl<T> Default for Paginator<T> {
+    fn default() -> Self {
+        Self {
+            items: Vec::new(),
+            ctoken: None,
+        }
+    }
+}
+
+impl<T> Paginator<T> {
+    /// Check if the paginator is exhausted, meaning that no more
+    /// items can be fetched.
+    ///
+    /// Equivalent to `paginator.ctoken.is_none()`.
+    pub fn is_exhausted(&self) -> bool {
+        self.ctoken.is_none()
+    }
+
+    /// Check if the paginator does not contain any data, meaning that it
+    /// is exhausted and does not contain any items.
+    pub fn is_empty(&self) -> bool {
+        self.items.is_empty() && self.is_exhausted()
+    }
+}