feat(balancer): Add rate providers to static attributes.

Adds the rate providers and additional attributes to balancers static attributes. These will help in the future to migrate some of the components to use the DCI.

Adds a small attributes module to tycho-substreams to make json encoding a bit easier.

substreams/crates/tycho-substreams/src/lib.rs

@@ -4,6 +4,7 @@ pub mod contract;
 mod mock_store;
 pub mod models;
 mod pb;
+pub mod attributes;
 
 pub mod prelude {
     pub use super::models::*;