[CBR-440] Document the estimateFee endpoint
[CBR-440] Document the estimateFee endpoint

Make explicit in the Swagger documentation that the spending password is
not required to estimate the fees.

input-output-hk/pos-haskell-prototype,input-output-hk/cardano-sl,input-output-hk/cardano-sl,input-output-hk/pos-haskell-prototype,input-output-hk/cardano-sl,input-output-hk/pos-haskell-prototype,input-output-hk/cardano-sl