Merge uiEvents into defaultConfig

As per discussions with @jonnywyatt , we think that defaultConfig
should be part of defaultConfig.
Helps reduce boilerplate such as  `this.uiEvents = uiEvents` within
each component’s constructor.
TODO bring other configs (i18nStrings, selectors, etc) into
defaultConfig
Merge pull request #187 from moneyadviceservice/defaultconfig-uievents-merge

Merge uiEvents into defaultConfig