[CLO] Implement query for WAS

### Goal

User shall able to query the weighted average of "spreads" on the loan asset.


### Spec

    ("PoolWaSpread", <PoolID>....)
    ("BondWaSpread", <BondID>....)


If it is fixed -> 0
If it is float -> number

Weighted averaged by current loan balance

### Parameters

* it takes a Maybe (pool id)
* if it nothing, then query all the asset in the collateral