[TEST] make sure that IndicesRequestTests is repeateable using the same seed

Remove the creation of a node client if not there before each test through setup method. `numClientNodes` makes sure that the client node gets created during suite cluster initialization.
1.3.3 release: add 1.3.4 version constant
[TEST] Use Shutdown API only if nodes are on 1.3.3 or newer to prevent shutdown problems
[BUILD] s/1.4.0.Beta-SNAPSHOT/1.4.0.Beta1-SNAPSHOT/
[BUILD] Release version should match latest version

This commit ensures that the latest version in our code is identical
to the project.version specified in the pom.xml file.
Nest original exception while creating NoShardAvailableActionException

Closes #7756
Core: go back to unbounded (scaling) thread pool for management threads (revert #7318)
Move forbidden api signature files to dev-tools.

This avoids the files showing up in the binary release, since .txt files
are copied.

closes #7917
closes #7921
Indices API: fixes GET Alias API backwards compatibility

For just the case when only the aliases are requested, the default indices options are to ignore missing indexes. When requesting any other feature or any combination of features, the default will be to error on missing indices.

Closes #7793
1.3.4 release: add 1.3.5 Version constant
Docs: Document the most important changes to zen discovery.

Closes #7746
Changed the root rest endpoint ('/') to use cluster service

Instead of issuing a redundant cluster state request.

Closes #7899
Snapshot/Restore: Allow custom metadata to specify whether or not it should be in a snapshot

Before this change all persistent custom metadata is stored as part of snapshot. It requires us to remove repositories metadata later during recovery process. This change allows custom metadata to specify whether or not it should be stored as part of a snapshot.

  Fixes #7900
Docs: Typoes on the range filter page
PluginManager: Fix config path extraction from plugin handle

The PluginManager had a subtle bug in case the config directory was not in the
es home directory - which is always true in case of packaging.

This fixes the plugin manager, so that when specifying a path.home and a
path.conf variable on the commandline, the plugin manager acts
appropriately.
Fix optimize behavior with 'force' and 'flush' flags.

This does the following:
* Make 'force' flag only build a merge if the delegate MP returned no merges
* Add async handling for 'flush' when 'waitForMerges' is false
* Remove flush at the beginning of optimize.  This is something the user can
  do if they wish, before calling optimize.

closes #7886
closes #7904
closes #7920
Fix compile breakage from backporting #7920
[TEST] Use canonical path for comparison rather than absolute path
[TEST] move fragile tests to BadApples rather than AwaitsFix
Test: AckClusterUpdateSettingsTests - only set publish_timeout to 0 after green