improve survey

[mrpalide]

Did you run make format && make check? Yes

Fixes #_

Changes:

• Encrypt survey with skycoin.asc key
• add timestamp in top of survey file

How to test this PR:

• in pkg->visor->visorconfig->survey.go change two line:
  1. line 22 -> rewardAddressBytes, err := os.ReadFile(conf.LocalPath + "/" + RewardFile) //nolint
  2. line 49 -> skycoinKeyPath := SkycoinKeyName
• make sure reward.txt with correct skycoin address be in local folder
• make build and run visor as root
• check node-info.json in local folder, it should be encrypted message