[STORE] Calculate Alder32 Checksums for legacy files in Store#checkIntegrity

Previously we didn't calculate this checksums even though we have a checksum
to compare. Since we now also verify checksums for legacy files #checkIntegrity
should also calculate the legacy checksums.

Closes #8407
[STORE] Synchronize operations that modify file mappings on DistributorDirectory

The rename(String, String) method doesn't allow this implementation to use a simple
concurrent map. There is a race during a rename operation where files are not fully
renamed but already visible via #listAll(). This inconsistency can lead to problems
when opening commit points since the pending_segments_N as well as segments_N are visible
but not yet atomically renamed.

Yet, non of the methods that are synced are long running such that adding sychronization
doesn't introduce bottlenecks here. The Direcotry#sync(...) method is not synchronized since
it doesn't change any mapping nor does it depend on the mapping.
[PING] Don't bubble up exception if we are shutting down and ping schedules get rejected
Core: Remove NestedDocsFilter, because it isn't used and also don't eagerly load it in bitset filter cache.

Closes #8414