Fixes #10044

@TarantoolBot document
Title: Configuration status is shown in `box.info.config` now

There is the `config:info([version])` method, but in order to access it
over iproto an application developer should add something like the
following into the application code:

```lua
_G.config = require('config')
```

It is not convenient, at least because it requires an attention from the
application developer and it can't be solved solely by an administrator.

Now, the `config:info('v2')` result is reported in the `config` field of
the `box.info` table. It is accessible over iproto if appropriate
privileges are granted for a calling user.