As per https://gitlab.com/meltano/meltano/issues/1601#note_296143046 we want a dedicated "Explore" main navigation item that displays the Data Source CTAs that link to their corresponding Explore page. This issue https://gitlab.com/meltano/meltano/issues/1826 was recently recategorized at tech debt, but aligns with this effort to get the intended `label`s needed for UI display