Move space configuration into a system space

Move space configuration into a system space.

Pre-configure space 255 to store information about other spaces.

Come up with a layout for space 255.

A possible layout is this:

object_id type_id name ....

We plan to store in this system the following data:
- spaces.
- space aliases. A name <-> object_id association for ease of use in clients
- field aliases. A name <-> number association to alias names to field numbers in a given space
- indexes, including index names. It should be possible to name an index.
- triggers of various types. We should be able to add before-insert triggers, before-apply-wal-row triggers and such in future.

This task also includes implementation of a bootstrapping algorithm, which reads the snapshot and configures spaces according to it.