Complete the backend Organizations API so server-side SDK users can administer organizations, memberships…

Complete the backend Organizations API so server-side SDK users can administer organizations, memberships…: a task in MiMo-V2.6-RL-harbor-code: MiMo-V2.6-RL Code (Harbor) (Harbor dataset). Only limit and offset belong in list query strings. When neither is supplied, emit no query string at all…