vshard: vshard.storage.info shows name

[TarantoolBot]

Related dev. issue: tarantool/vshard#426
Related doc. issues: #3943, #3944

Product: Tarantool, vshard
Since: 3.0, 0.1.25
Root document: https://www.tarantool.io/en/doc/latest/reference/reference_rock/vshard/vshard_storage/
SME: @ Totktonada, @ Serpentian

Details

When identification_mode is name_as_key, persisted master and
replicaset name is shown in vshard.storage.info:

tarantool> vshard.storage.info()
---
- replicasets:
    replicaset_1:
      name: replicaset_1
      master:
        uri: admin@localhost:3302
        name: replica_1_a
  ...

Requested by @ Serpentian in tarantool/vshard@559c75c.