Inventory App (edit-folder): Use documented react-intl patterns instead of stripes.intl

Retrieving the intl object from this.context.intl or the stripes god object (stripes.intl) is a deprecated pattern.

Update this repo to only use react-intl constructs outlined at https://github.com/folio-org/stripes-core/blob/master/doc/i18n.md

Use <FormattedMessage>, <FormattedDate>, and <FormattedTime>. The functions-only react-intl API - formatMessage(), formatDate(), and formatTime() (accompanied by injectIntl) - shouldn't be needed.

React Intl docs: https://github.com/yahoo/react-intl/wiki