Universal admin interface

We need an universal admin interface that allow to manage data stored on sites.

Features needed:
- Query/Modify/Delete ZeroTalk and ZeroBlog (and other sites) database without any source code modifications. (using only configuration files)
- Query/modify users limit using it
- [ ] Create sample configuration file for ZeroTalk and ZeroBlog (xml?, json?, js?, yaml?)
- [ ] Layout mockups
- [ ] ...Coding

This would be huge benefit for all ZeroNet sites, so it would be really nice if someone would be able to take this task, so I will be able to focus on core modifications.

No files, tests, or entry points are named. Start by reviewing the requested ZeroTalk and ZeroBlog database operations, user-limit management, configuration format, and mockups, then define the scope and acceptance criteria. Done should mean the agreed interface and configuration approach cover the selected sites without source changes.

索引モデルが issue の本文から書いたものです。