v1.18: blockstore: scaffolding for chained merkle root conflict detection (backport of #719)

[mergify]

Split from #102
The scaffolding needed to detect chained merkle root conflicts for sending duplicate proofs:

• feature gate
• window service processing
• find previous consecutive erasure set
• check forward / backwards chaining

Contributes to solana-labs#34897

---

This is an automatic backport of pull request #719 done by Mergify.

[mergify]

Cherry-pick of 411fdc9 has failed:

On branch mergify/bp/v1.18/pr-719
Your branch is up to date with 'origin/v1.18'.

You are currently cherry-picking commit 411fdc9312.
  (fix conflicts and run "git cherry-pick --continue")
  (use "git cherry-pick --skip" to skip this patch)
  (use "git cherry-pick --abort" to cancel the cherry-pick operation)

Changes to be committed:
	modified:   core/src/window_service.rs
	modified:   ledger/src/blockstore.rs
	modified:   ledger/src/blockstore_db.rs
	modified:   ledger/src/blockstore_meta.rs
	modified:   ledger/src/shred.rs

Unmerged paths:
  (use "git add <file>..." to mark resolution)
	both modified:   sdk/src/feature_set.rs

To fix up this pull request, you can check it out locally. See documentation: https://docs.github.com/en/pull-requests/collaborating-with-pull-requests/reviewing-changes-in-pull-requests/checking-out-pull-requests-locally

[codecov-commenter]

Codecov Report

Attention: Patch coverage is 61.21495% with 83 lines in your changes are missing coverage. Please review.

Project coverage is 81.5%. Comparing base (c4e7b6b) to head (e6a3555).

Additional details and impacted files

@@            Coverage Diff            @@
##            v1.18     #729     +/-   ##
=========================================
- Coverage    81.6%    81.5%   -0.1%     
=========================================
  Files         827      827             
  Lines      224878   225085    +207     
=========================================
+ Hits       183512   183643    +131     
- Misses      41366    41442     +76