Add more traces in case of failure when testing with actual plugins
(cherry picked from commit 0b2ff1e)
Added extra rest endpoint for get settings api.
Added rest test to also test the get settings' prefix option.
Change the `sort` boolean option in percolate api to the sort dsl available in search api.

Closes #4625
Deprecated disable allocation decider which has the following options:
`allocation.disable_new_allocation`, `allocation.disable_allocation`, `allocation.disable_replica_allocation`,
in favour for the enable allocation decider which has a single option `allocation.enable` wich can be set to the following values:
`none`, `new_primaries`, `primaries` and `all` (default).

Closes #4488
remove default `_all` for `type` and `index` if these are missing in REST tests

If a type or path is missing in the REST test yaml file, it is
automatically replaced with _all. This makes it hard to test changes
in the api, for example adding the possibility to leave the index
blank in addition to _all and * in the uri.

closes #4657
[DOCS] Added documentation for SameShardAllocationDecider

Closes #4615
give the compiler more memory, otherwise it fails sometimes
[DOCS] Fix HTTP endpoints after stats API changes
Added `action.destructive_requires_name` that controls whether wildcard expressions and `_all` is allowed to be used for destructive operat Also the delete index api requires always an index to be specified (either concrete index, alias or wildcard expression)

Closes #4549 #4481
improve buffered output
- use the same buffer size if wrapping a buffered output
- directly call flush on the checksum wrapper