Minor Improvements

[Martin-Molinero]

• Minor adjustment so that optional configurations are requested to the user if they have no value in interactive mode, in non interactive will use the default value if any
• Log configuration messages once
• Add data purchase limit for optimization. Closes https://github.com/QuantConnect/lean-cli/issues/425

Related https://github.com/QuantConnect/lean-cli/pull/428

Sanity tested running live deployments and optimizations