fix(curve): some general fixes including

Bytes decoding from BalanceChange, sort  BlockBalanceDeltas, transform `0xeeee...` into `0x000...` for consistency, and add a placeholder for missing tokens in `get_token_from_pool`.

substreams/ethereum-curve/src/abi/mod.rs

@@ -5,6 +5,6 @@ pub mod crypto_swap_ng_factory;
 pub mod meta_registry;
 pub mod tricrypto_factory;
 pub mod main_registry;
-pub mod ERC20;
+pub mod erc20;
 pub mod meta_pool_factory;
 pub mod crypto_swap_registry;