Changing the disk media type on the fly

[drbasic]

It is necessary to make it possible for users to change the disk media-type without any noticeable disruption to reading and writing processes.

[drbasic]

docs: #3000

1. Create and destroy volume link tag #1 #3039
2. Persist follower disks #3147
3. Added CopyToSgList() with different block size #3214
4. Linked disk bandwidth config #3221
5. Teach TGetDeviceForRangeCompaction to disallow every operation; teach TMigrationTimeoutCalculator to work without PartitionConfig provided; add method for FollowerDiskId printing #3304
6. Persist migration progress for linked disks #3315
7. Save partition actors and wrappers in stack #3383
8. Predefined CopyVolumeClientId to make IO without session #3387
9. Propagate link to follower #3562
10. Revert "Propagate link to follower (#3562)" #3726 откат
11. Propagate link to follower (exist DB-schema not changed) #3776
12. Added a policy to use direct copying or not #3945
13. Make follower media kind non-optional since it immediately known #3946
14. Set AllZeroes flag in ReadBlocks response for BlobStorage-based disks #3962
15. Improve performance of checking IsAllZeroes. Fix ASAN #3972
16. Refactor actors ownership for migration-related actors #3973
17. Introduce TVolumeAsPartitionActor #4025
18. Fill follower disk when link created #4091
19. Test reboot tablets during follower fill #4109
20. issue-2999: Introduce ISwitchableBlockStore #4308
21. Introduce ISwitchableSession #4356
22. VolumeProxy support for ExactDiskIdMatch flag #4395
23. Send PrincipalDiskId in mount response #4399
24. Move volume_label.* to model #4465
25. Set PrincipalDiskId in VolumeConfigToVolume() #4491
26. Added new state for link LeadershipTransferred. Blocks requests according to ELeadershipStatus #4539
27. Added BeforeSwitching() and AfterSwitching() for ISwitchableBlockStore #4540
28. Live migration to the new leader volume. #4448
29. Unregister metrics with RemoveSubgroupChain() #4661
30. Use logical disk id for metrics #4667