[CSM-378] Review suggestions: improve code readability
[CSM-378] Review suggestions: improve code readability

Use custom datatype with custom lenses as a state of `InputPickerState`

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