[CSL-875] Remove DEV_MODE from Pos.CLI
[CSL-875] Remove DEV_MODE from Pos.CLI

There are three CLI arguments that only exist in DEV_MODE: 'flatDistr',
'bitcoinDistr', 'expDistr'. This commit removes DEV_MODE around them, but
simply doesn't include them into the optparse-applicative parser when
'isDevelopment' is enabled.

Basically, this commit doesn't change anything for anyone.

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