feat: Virtual values as a OneOf in protobuf schema

[thenswan]

Description:
This PR changes Virtual Values, so they are represented as a OneOf in protobuf schema, hence changes in virtual_map_state.proto:

• Add VirtualLeaf;
• Add QueueState;
• Add VirtualMapValue;
• Update state validator (tested with state generated using :app:run).

Related issue(s):
Fixes #20288

Checklist

• Documented (Code comments, README, etc.)
• Tested (unit, integration, migration, etc.)

[lfdt-bot]

🎉 Snyk checks have passed. No issues have been found so far.

✅ security/snyk check is complete. No issues have been found. (View Details)

[codacy-production]

Coverage summary from Codacy

See diff coverage on Codacy

Coverage variation	Diff coverage
✅ -0.03% (target: -1.00%)	✅ 77.45%

Coverage variation details

	Coverable lines	Covered lines	Coverage
Common ancestor commit (34c268b)	101956	76545	75.08%
Head commit (0c3b701)	101939 (-17)	76500 (-45)	75.04% (-0.03%)

Coverage variation is the difference between the coverage for the head and common ancestor commits of the pull request branch: <coverage of head commit> - <coverage of common ancestor commit>

Diff coverage details

	Coverable lines	Covered lines	Diff coverage
Pull request (#20317)	102	79	77.45%

Diff coverage is the percentage of lines that are covered by tests out of the coverable lines that the pull request added or modified: <covered lines added or modified>/<coverable lines added or modified> * 100%

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[codecov]

Codecov Report

❌ Patch coverage is 71.56863% with 29 lines in your changes missing coverage. Please review.

Files with missing lines	Patch %	Lines
...java/com/swirlds/state/merkle/MerkleStateRoot.java	0.00%	11 Missing ⚠️
...main/java/com/swirlds/state/merkle/StateUtils.java	45.45%	6 Missing ⚠️
...tate/merkle/disk/OnDiskWritableSingletonState.java	50.00%	4 Missing ⚠️
...java/com/swirlds/state/merkle/VirtualMapState.java	92.30%	2 Missing ⚠️
...m/swirlds/state/merkle/disk/OnDiskQueueHelper.java	85.71%	0 Missing and 2 partials ⚠️
...ds/state/merkle/disk/OnDiskWritableQueueState.java	81.81%	0 Missing and 2 partials ⚠️
...ds/state/merkle/disk/OnDiskReadableQueueState.java	50.00%	0 Missing and 1 partial ⚠️
...irlds/state/merkle/disk/OnDiskWritableKVState.java	90.90%	0 Missing and 1 partial ⚠️

@@             Coverage Diff              @@
##               main   #20317      +/-   ##
============================================
- Coverage     71.17%   71.14%   -0.04%     
+ Complexity    24044    24032      -12     
============================================
  Files          2647     2645       -2     
  Lines        102051   102034      -17     
  Branches      10576    10581       +5     
============================================
- Hits          72633    72590      -43     
- Misses        25460    25488      +28     
+ Partials       3958     3956       -2     

Files with missing lines	Coverage Δ	Complexity Δ
.../com/swirlds/state/merkle/disk/OnDiskIterator.java	84.00% <100.00%> (ø)	7.00 <0.00> (ø)
...irlds/state/merkle/disk/OnDiskReadableKVState.java	81.25% <100.00%> (+1.25%)	5.00 <2.00> (+1.00)
...tate/merkle/disk/OnDiskReadableSingletonState.java	100.00% <100.00%> (ø)	2.00 <1.00> (ø)
...irlds/state/merkle/disk/OnDiskSingletonHelper.java	100.00% <100.00%> (+40.00%)	2.00 <2.00> (ø)
...ds/state/merkle/disk/OnDiskReadableQueueState.java	88.88% <50.00%> (ø)	3.00 <0.00> (ø)
...irlds/state/merkle/disk/OnDiskWritableKVState.java	84.61% <90.90%> (+2.79%)	8.00 <5.00> (+2.00)
...java/com/swirlds/state/merkle/VirtualMapState.java	81.91% <92.30%> (-0.39%)	32.00 <0.00> (ø)
...m/swirlds/state/merkle/disk/OnDiskQueueHelper.java	75.00% <85.71%> (-3.95%)	7.00 <5.00> (+1.00)	⬇️
...ds/state/merkle/disk/OnDiskWritableQueueState.java	87.50% <81.81%> (-3.81%)	5.00 <0.00> (ø)
...tate/merkle/disk/OnDiskWritableSingletonState.java	68.75% <50.00%> (-2.68%)	3.00 <2.00> (ø)
... and 2 more

... and 18 files with indirect coverage changes

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[tinker-michaelj]

LGTM, tyvm @thenswan !

[jasperpotts]

Approve with a few comments/questions but none blocking