Refactor blog module and remove blog-related functionality

- Removed blog router and associated API endpoints.
- Deleted blog persistence functions and related query parameters.
- Removed blog schemas and models from the codebase.
- Introduced common crate for shared types, including DateTimeWithTimeZoneWrapper.
- Added Thought and Follow models with corresponding migrations.
- Updated dependencies in Cargo.toml files to reflect changes.
- Adjusted tests to remove references to the blog module.

thoughts-backend/tests/api/mod.rs

@@ -1,11 +1,9 @@
 use api::setup_router;
 use utils::testing::setup_test_db;
 
-mod blog;
 mod root;
 mod user;
 
-use blog::*;
 use root::*;
 use user::*;
 
@@ -30,15 +28,3 @@ async fn user_main() {
     test_post_users_error(app.clone()).await;
     test_get_users(app).await;
 }
-
-#[tokio::test]
-async fn blog_main() {
-    let db = setup_test_db("sqlite::blog?mode=memory&cache=shared")
-        .await
-        .expect("Set up db failed!");
-
-    let app = setup_router(db);
-    test_post_users(app.clone()).await;
-    test_post_blogs(app.clone()).await;
-    test_get_blogs(app).await;
-}