Update Datetime handling in API and DB layers

Changed the handling of start, stop, and update timestamp fields in ReportRowInnerTimeEntry data structure from strings to DateTime objects in the API layer. Also updated the data persisting in DB layer to use these new datetime objects and introduced additional columns for server_updated_at, server_deleted_at and tags.

src/toggl_api/api_client.rs

@@ -1,4 +1,4 @@
-use reqwest::{Client, RequestBuilder, Response, Url};
+use reqwest::{Client, RequestBuilder, Response};
 use serde_json::Value;
 use std::collections::HashMap;
 use std::time::Duration;

src/toggl_api/types.rs

@@ -25,9 +25,9 @@ pub struct ReportRow {
 pub struct ReportRowInnerTimeEntry {
     pub id: u64,
     pub seconds: u32,
-    pub start: String,
-    pub stop: String,
-    pub at: String,
+    pub start: DateTime<Utc>,
+    pub stop: DateTime<Utc>,
+    pub at: DateTime<Utc>,
 }
 
 #[derive(Debug, Clone, Serialize, Deserialize)]