For BZ#1334374: Add a new Reseller chapter in `user and identity management guide`. Describe the new relationship between projects and domains, and the use case this allows. Include demonstration procedure. Also, move the Hierarchical Multitenancy (HMT, aka nested tenants) content to this chapter.
Assigning to Martin for review.
Added in suggestions from Nathan, moved content into `Project` mgmt.
Looks good to me. Merged.