[Malleability Immutable] Enforce immutability for Block (cluster)

[UlyanaAndrukhiv]

Please do not review this PR. It is in progress.

Closes: #7277

Changes

• Added UntrustedBlock model.
• Added cluster.Block validations for constructor.
• Added unit tests for constructor.
• Updated constructor for cluster.Payload to use Untrusted model to be consistent with other constructors.
• Added unit tests for cluster.Payload constructor.
• Removed unused SyncedBlock and SyncedClusterBlock types.
• Removed unused UntrustedBlock type from model/messages/consensus.go.

[codecov-commenter]

Codecov Report

Attention: Patch coverage is 44.54545% with 122 lines in your changes missing coverage. Please review.

Project coverage is 41.34%. Comparing base (fbd8690) to head (f29a207).

Files with missing lines	Patch %	Lines
utils/unittest/cluster_block.go	0.00%	46 Missing :warning:
module/buffer/pending_cluster_blocks.go	0.00%	26 Missing :warning:
utils/unittest/fixtures.go	0.00%	11 Missing :warning:
module/builder/collection/builder.go	66.66%	5 Missing and 2 partials :warning:
storage/badger/procedure/cluster.go	66.66%	5 Missing and 2 partials :warning:
model/messages/collection.go	60.00%	4 Missing and 2 partials :warning:
model/cluster/block.go	85.18%	4 Missing :warning:
engine/collection/compliance/core.go	50.00%	2 Missing and 1 partial :warning:
engine/collection/message_hub/message_hub.go	70.00%	2 Missing and 1 partial :warning:
model/messages/synchronization.go	57.14%	2 Missing and 1 partial :warning:
... and 2 more

Additional details and impacted files

@@                   Coverage Diff                    @@
##           feature/malleability    #7553      +/-   ##
========================================================
+ Coverage                 40.30%   41.34%   +1.04%     
========================================================
  Files                      2121     2187      +66     
  Lines                    186907   193795    +6888     
========================================================
+ Hits                      75325    80123    +4798     
- Misses                   105272   106988    +1716     
- Partials                   6310     6684     +374     

Flag	Coverage Δ
unittests	41.34% <44.54%> (+1.04%)	:arrow_up:

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