box: support TT_* uri env vars with query params

`TT_LISTEN` and `TT_REPLICATION` environment variables were interpreted
by `box.cfg()` in a confusing way if query parameters with values are
present. For example, `localhost:3301?transport=plain` was interpreted
as the following map: `{['localhost:3301?transport'] = 'plain'}`. Later,
`box.cfg()` looks into this map for known URI fields like `login`,
`password`, `uri`, `host`, `service` and so on. It found nothing and
doesn't start a listening socket.

The reason of such a behaviour is that the environment value is
interpreted as a mapping in the `key=value,key=value` format, because
there is `=` in it.

The patch changes this behavior for an `key=value,key=value` environment
variable that contains `?` in a key: now such a value is not interpreted
as a mapping.

Note: Everything said above is also applicable to the so called
multilisten case: when several URIs are defined in the environment
variable. The following URI list is interpreted correctly now.

NOWRAP
```sh
export TT_LISTEN=localhost:3301?transport=plain,localhost:3302?transport=plain
```
NOWRAP

Note 2: Examples are given with the `plain` transport, which is default,
but the query parameters are the way to define TLS options. They're
supported in Tarantool Enterprise Edition, see [1].

Fixes #9539

NO_DOC=bugfix

[1]: https://www.tarantool.io/en/doc/latest/enterprise/security/#traffic-encryption