Remove humps from ui package
Right now [humps] (https://gitlab.coko.foundation/pubsweet/pubsweet/blob/master/packages/ui/src/atoms/Icon.js#L21) is only used in Icon.js to change icon names to camel case. The same effect can be achieved with [camelCase] (https://lodash.com/docs/4.17.5#camelCase) and [upperFirst] (https://lodash.com/docs/4.17.5#upperFirst) from lodash, which is already used for other things in the same package. We should keep the number of dependencies as low as possible.