Tweaking upgrade test to improve reliability.
testDanglingIndicesConflictWithAlias - wait for node left to be processed

O.w. delete index command may time out waiting for the node that left to confirm deletion
Docs: cross_type query needs to be cross_fields

Closes #8021
Fixing test to allow decimal numbers for load.
Updating test to support Windows file descriptor count (-1)
Docs: Removing escape character

The escape character `\` doesn't work and should be removed from the documentation.

Closes #8029
Add debug logging to help diagnose intermittent upgrade test failures.

Also fixed indentation in ElasticsearchMergePolicy.
Update cat.nodes regex

Support for multi-word node names like 'Henry "Hank" McCoy'
Snapshot/Restore: fix snapshot of a single closed index

Snapshot of a closed index can leave snapshot hanging in initializing state.

Fixes #8046
Docs: add the predefined language-specific stopword lists to stop-tokenfilter.asciidoc
Docs: adds note about using null_value with dynamic templates

Closes #7874
Docs: Adding community-contributed Scout plugins

Scout plugins for reporting key node, cluster, and index health metrics.

Closes #7937
Netty: Support to bind on multiple host/port pair

TODO: Documentation
Incorporated review comments #1