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/models/src/domains/follow.rs

@@ -0,0 +1,32 @@
+use sea_orm::entity::prelude::*;
+
+#[derive(Clone, Debug, PartialEq, DeriveEntityModel, Eq)]
+#[sea_orm(table_name = "follow")]
+pub struct Model {
+    #[sea_orm(primary_key)]
+    pub follower_id: i32,
+    #[sea_orm(primary_key)]
+    pub followed_id: i32,
+}
+
+#[derive(Copy, Clone, Debug, EnumIter, DeriveRelation)]
+pub enum Relation {
+    #[sea_orm(
+        belongs_to = "super::user::Entity",
+        from = "Column::FollowerId",
+        to = "super::user::Column::Id",
+        on_update = "NoAction",
+        on_delete = "Cascade"
+    )]
+    Follower,
+    #[sea_orm(
+        belongs_to = "super::user::Entity",
+        from = "Column::FollowedId",
+        to = "super::user::Column::Id",
+        on_update = "NoAction",
+        on_delete = "Cascade"
+    )]
+    Followed,
+}
+
+impl ActiveModelBehavior for ActiveModel {}