[FEAURE] add setup-wizard http endpoint
[FEATURE] validate the existence of each config property
[TEST] check existence of each config property
[CHORE] move validation to API core
[TEST] postgres URL, ripple-rest URL and ripple address
[FEATURE] validate ripple address, porstgres url, ripple-rest url
[CHORE] breakup public http controllers.
[TEST] validate trust amount
[FEATURE] validate trust amount
Merge branch 'wizard' of github.com:ripple/gatewayd into wizard
[BUG] Default config params to {}.
[TEST] config property validation
[CHORE] add a success message
[BUG] validate config properties
Merge branch 'wizard' of https://github.com/ripple/gatewayd