Implement `RtcStats` feature for native platforms

[rogurotus]

Synopsis

Implement get stats for native platform.

Checklist

• Created PR:
  • [x] In draft mode
  • [x] Name contains Draft: prefix
  • [x] Name contains issue reference
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• [x] Documentation is updated (if required)
• [x] Tests are updated (if required)
• [x] Changes conform code style
• [x] CHANGELOG entry is added (if required)
• [x] FCM (final commit message) is posted
  • [ ] and approved
• [ ] Review is completed and changes are approved
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[rogurotus]

FCM:

Implement get stats for native (#84)

[evdokimovs]

Implemented in #173 with different approach.