Node ate obviously incorrect config

[cthulhu-rider]

Context

Node silently started with this config (attached only incorrect part):

storage:
  shard:
    0:
      blobstor:
      - path: /srv/neofs/data0/blobovnicza
        type: blobovnicza
      - path: /srv/neofs/data0
        type: fstree
      metabase:
        path: /srv/neofs/meta/metabase0.db
      pilorama:
        path: /srv/neofs/meta/pilorama0.db
      writecache:
        path: /srv/neofs/meta/write_cache0
    default:
      blobstor:
        blobovnicza:
          depth: 1
          opened_cache_capacity: 32
          size: 4gb
          width: 8
        compress: true
        depth: 4
        perm: '0644'
        small_object_size: 150kb
      gc:
        remover_batch_size: 100
        remover_sleep_interval: 1m
      metabase:
        max_batch_size: 1000
        perm: '0644'
      pilorama:
        max_batch_delay: 10ms
        max_batch_size: 1000
        no_sync: true
      writecache:
        capacity: 64gb
        enabled: true
        max_object_size: 128mb
        memcache_capacity: 2gb
        small_object_size: 128kb
        workers_number: 30
    1:
      blobstor:
      - path: /srv/neofs/data1/blobovnicza
        type: blobovnicza
      - path: /srv/neofs/data1
        type: fstree
      metabase:
        path: /srv/neofs/meta/metabase1.db
      pilorama:
        path: /srv/neofs/meta/pilorama1.db
      writecache:
        path: /srv/neofs/meta/write_cache1
  shard_pool_size: 600
  shard_ro_error_threshold: 30

As we can see storage.shard.default.blobstor section is formed incorrectly according to docs. Also compress and small_object_size must be shard config, not blobstor.

Expected behavior

Node run fails.

Current behavior

Node starts silently.

Possible improvements

• provide config validator which shares code with neofs-node app (maybe its command?)
• provide config defaulter which accepts source config and outputs to-be-used config (can be merged with validator)
• print the configurations used as a result in the application log

Versions

• neofs-node v0.35.0

[cthulhu-rider]

nspcc-dev#2276