Core: Cleanup non nested filter to not flip the bits in the FixedBitSet returned by the wrapped filter.

If the filter producing the FBS were to be cached then it would flip bits each time the NonNestedDocsFilter was executed.
In our case we cache the NonNestedDocsFilter itself so that didn't happen each time this filter was used.
However the hashcode of NonNestedDocsFilter and NestedDocsFilter was the same, since NonNestedDocsFilter directly used NestedDocsFilter#hashCode()

Closes #8227
Closes #8232
Documented that HTTP pipelining is not supported
Test: The non-nested filter should be cached in order for it to produce a FBS
Delete by query: wrap parent filter in FixedBitSetCachingWrapperFilter.

When the none filter cache is used this is required.
Facets: wrap parent filter in FixedBitSetCachingWrapperFilter.

None filter doesn't return FBS
Added left over FixedBitSetCachingWrapperFilter wrapping.
Docs: Update multi-get.asciidoc

Duplicate word

Closes #8228
Introduce ES_USE_IPV4 flag in .bat files

Synchronize the .bat files with the .sh ones by adding ES_USE_IPV4
flag. Higher branches (from 1.4 included) extend this functionality by
introducing elasticsearch.in.bat to mirror elasticsearch.in for *nix
systems.

Relates #8237
Improve handling of multicast binding exceptions

In case the multicast binding fails (due to socket errors), abort zen
pinging code and throw a better error message
Relates #8225
Tests: Removed use of put_alias without an index name

Relates to #7863
Add an inline link referencing directory structure

Adds a link to the directory structure in the sentence that brings up the Linux package/RPM.

- Fixes some minor grammar issues (e.g., capitalization).
[ENGINE] Add current translog ID to commit meta before closing

Today we simply close the IW when we have to open a new one if ie.
we change merge settings. Yet, the API is deprecated and under the hood
it commits the IW. For safety we should add the current translog ID and
use rollback instead to not wait for merges.
s/MapBuilder/singletonMap in InternalEngine