[razdoburdin]

Follow-up the #369

This PR unify the code between concurrent and non-concurrent implementation of MutableVamana. The goal is to reuse code without any behavioral changes.

Changes list:

1. concurrent/spinlock.h. The concurrent::SpinLock is now an alias to lib::SpinLock (VecSim uses concurrent::SpinLock, so we should keep it). No changes in non-concurrent code.
2. concurrent/translation.h. The file is deleted. The consumers of the concurrent::IDTranslator now use svs::IDTranslator. 3 methods were copy-pasted from concurrent::IDTranslator to svs::IDTranslator.
3. concurrent/iterator.h. The vamana::concurrent::BatchIterator class is kept. The common logic between vamana::concurrent::BatchIterator and vamana::BatchIterator was moved to vamana::detail::BatchIteratorBase, whilch is now CRTP base for both vamana::concurrent::BatchIterator and vamana::BatchIterator.
4. concurrent/consolidate.h. The concurrent::BulkUpdate class is removed, vamana::BulkUpdate is now used instead of it. conurrent::GraphConsolidator::apply_update method is removed as unused.
5. concurrent/dynamic_search_buffer.h. The conurrent::MutableBuffer inherits now from vamana::MutableBuffer. Concurrent version contain a bug fix to backport in the non-concurrent index. After the backporting, conurrent::MutableBuffer will be fully replaced by vamana::MutableBuffer.
6. concurrent/graph_concepts.h. The svs::graph::MemoryGraph concept has now an additional template parameter: AddEdgeReturn. For concurrent graph it is used with AddEdgeReturn = concurrent::graphs::AddEdgeResult, for non-concurrent with AddEdgeReturn = size_t. ImmutableMemoryGraph and graphs_equal are removed. There consumers uses the analogs svs::graph::ImmutableMemoryGraph and svs::graph::graphs_equal.
7. concurrent/multi.h. Common helpers for assemble from disk and stream are added.
8. concurrent/blocked_data.h. SimpleData for std::vector and lib::SegmentedVector is unified.
9. concurrent/graph.h. Reuse the same saving/loading logic.
10. concurrent/vamana_build.h. Reuse vamana::OptionalTracker in concurrent code.
11. concurrent/dynamic_index.h. Reuse the same saving/loading and calibration logic.

Next iteration of unification will be done, after backporting of the minor fixes from concurrent index.

[ethanglaser]

Looking pretty good, a few comments. Ran CI from private repo and no issues.

[ethanglaser]

The concurrent README states concurrent spinlock adds move/copy functionality which would be lost with this (https://github.com/intel/ScalableVectorSearch/blob/main/include/svs/concurrent/README.md?plain=1#L127) - is it worth trying to preserve or should the README be updated?

[razdoburdin]

Readme should be updated. I think all the refactoring stages should be done first.