[DOCS] Fixed file:/// URL for installing plugins
[DOCS] Added documentation for CAT Aliases API

Added asciidoc. Added new lines in java class.
Added no-cache infrastucture the the filter cache.

During query parsing if a filter is encountered that extends from NoCacheFilter then the filter will not be given to the filter cache (also not wrapped in FilterCacheFilterWrapper).
Also if a filter directly or indirectly wraps a NoCacheFilter then that filter will also not be cached.

Relates to #4757
Made sure that any filter that wraps a p/c filter (has_child & has_parent) either directly or indirectly will never be cached by making CustomQueryWrappingFilter extend from NoCacheFilter.

Closes #4757
Consume the entire weight and pre compute the DocIdSets for all segments instead of keeping the weight around and build a DocIdSet when a segment is being processed. This fixes issues where the has_child / has_parent filter produce no results or errors on subsequent scan requests.

Also made CustomQueryWrappingFilter implement Releasable in order to cleanup the pre-computed DocIdSets.

Closes #4703
[SPEC] Removed create.json
Create is a special API that is most simply and safely
implemented by calling the index() api with op_type
set to true.
[SPEC] Various API fixes
Including:
* change some string params to list
* make some params or bodies required
* removed incorrect URLs
* removed incorrect params
* Fixed name of pending_tasks
fix IndexOutOfBoundsException on _all field without tokens and keyword analyzer

fix AllEntries to only compute boost when there are actually some Entries available for the _all field

Closes #4771
[TESTS] Mapping update might get applied before the first document is indexed on replica, so it is better not to check if the new field isn't available before re-indexing first document.
Documentation typo.
[TEST] Added create api (hardcoded) to REST tests suite as it has no spec but it's just a variation of the index api
Fix test bug: test expects at least one child document.
[TEST] Better fix for missing create spec

create is a shortcut to index with op_type=create that the clients support
Reference docs fixes

* Make it clearer that `aggs` is an allowed synomym
  for the `aggregations` key
* Fix broken example in for datehistogram, `1.5M` is
  not an allowed interval
* Make use of colon before examples consistent
* Fix typos
Added base Request class for read operations that usually happen on the master but can be executed locally.
Added base TransportAction class for master read operations that execute locally or not depending on the request class (local flag).

Added support for local flag where missing, in a backwards compatible manner:
     - IndicesExistsRequest
     - GetAliasesRequest (get alias api, aliases exist api)
     - TypesExistsRequest
     - GetIndexTemplatesRequest (get template, template exists)
     - GetSettingsRequest
     - GetRepositoriesRequest
     - PendingClusterTasks

 Added parsing of the local flag where missing in Rest*Action.

 Updated SPEC adding local flag param where missing and added REST tests that contain use of the local flag where it was just added.

Closes #3345
master_timeout parameter is now taken into account when calling cluster pending tasks api through the REST layer

Closes #4806
[TEST] Added missing newline at end of YAML test file
[TEST] Added missing \n at end of YAML files, quoted * and fixed indentation
Accept the same boolean values in RestRequest

Added `no` as a possible value to `paramBooleanAsOptional`, also reused existing code from `Booleans.parseBoolean`

Closes #4808
Fix logging on immediate exit on start

If elasticsearch was started in the foreground an immediate exit on startup
led to logging in the logfile, where as when starting in the background,
an immediate exit logged to stdout.

Closes #4805