Added monitoring, limited concurent connections (#245)

* reduced the default, and added environment override.

* Using parse is more stable and doesn't fail CI this time :P

* Added support for monitoring
This support is currently basic, but it can be improved later down the road.

* Forgot scheduler file

* Added health check

* Cargo fix

* Update cargo.lock to avoid action fails.

Co-authored-by: Geometrically <18202329+Geometrically@users.noreply.github.com>

src/database/postgres_database.rs

@@ -8,7 +8,6 @@ const MIGRATION_FOLDER: &str = "migrations";
 
 pub async fn connect() -> Result<PgPool, sqlx::Error> {
     info!("Initializing database connection");
-
     let database_url = dotenv::var("DATABASE_URL").expect("`DATABASE_URL` not in .env");
     let pool = PgPoolOptions::new()
         .min_connections(