Docs: typo?

Closes #7458
[SNAPSHOT] Add BWC layer to .si / segments_N hashing

Due to additional safety added in #7351 we compute now a strong hash for
.si and segments_N files which are compared during snapshot / restore.
Old snapshots don't have this hash which can cause unnecessary copying
of large amount of data. This commit adds the ability to fetch this
hash from the blob store if needed.

Closes #7434
Test: mute test until we know what is going on
[Test] rewrite testNoMasterActions to use latest tooling

The test's timeout checks were thrown off by a client created randomly (when the timer was running).

Closes #7432
Tests: Fix FileBasedMappingsTests by using the mappings API instead of field mappings.
Tests: Temporarily ignore SnapshotBackwardsCompatibilityTest
Internal: Add LZF safe encoder in LZFCompressor

Selecting the safe encoder fixes a 64bit JVM crash on big-endian architectures with
LZF UnsafeChunkEncoderBE.

closes #7466
Revert part of change in #7466 to fix issue because encoder is not threadsafe so cannot be shared
Internal: Add all unsafe variants of LZF compress library functions to forbidden APIs.

The "optimized" encoders/decoders have been unreliable and error prone.
Also, fix LZFCompressor.compress to use LZFEncoder.safeEncode, which
creates a new safe encoder, instead of using a shared encoder (which
is not threadsafe).

closes #7468
[Test] testLargeClusterStatePublishing - bound max shard no to number of nodes and set replica count to 0

ensureGreen sometimes times out due to too many shards and GC kicking in
Parent/child: If _parent field points to a non existing parent type, then skip the has_parent query/filter

Closes #7362
Closes #7349
Parent/child: Add missing support for the field data loading option to the `_parent` field.

Closes #7394
Closes #7402