mock/rest: Add initial documentation
mock/rest: Simple request handler backend implementation using shelve

At the moment it support 'folders' operations except for
PUT /folders/
mock/rest: 'folders' ops almost done in Mock server

Exception is PUT /folders/ddd to update a folder properties
mock/rest: keep 'temp' director around since we are going to use runtime
mock/rest: Server documentation from 'www' directory