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/Cargo.toml

@@ -19,3 +19,5 @@ sea-orm = { workspace = true, features = [
 ] }
 validator = { workspace = true, features = ["derive"] }
 utoipa = { workspace = true }
+
+common = { path = "../common" }