Mainnet Validators and Liteserver owners

Please update your node software (see "Target versions")

Instructions for update. Note new section 5 for validators and section 6 for Liteserver owners.

Target versions:
mytonctrl b9d5937
validator 692211f

This update is mandatory for validators and lite servers.

Update includes:
- LS improvements: remote runmethods with full c7 and libs, caching, logging
- Precise control of open files
- Improvement of validator synchronization