Aggregations: Do not take deleted documents into account in aggregations filters.

Since aggregators are only called on documents that match the query, it never
gets called on deleted documents, so by specifying `null` as live docs, we very
likely remove a BitsFilteredDocIdSet layer.

Close #8540
Aggregations: Fix geohash grid aggregation on multi-valued fields.

This aggregation creates an anonymous fielddata instance that takes geo points
and turns them into a geo hash encoded as a long. A bug was introduced in 1.4
because of a fielddata refactoring: the fielddata instance tries to populate
an array with values without first making sure that it is large enough.

Close #8507
Tests: Fix test bug in Filter[s]Tests that made it throw a version conflict.
[TEST] use logger level from test class annotation also in external nodes

closes #8552
[root mappers] fix conflict when updating mapping with _all disabled

_all reports a conflict since #7377. However, it was not checked if _all
was actually configured in the updated mapping. Therefore whenever _all
was disabled a mapping could not be updated unless _all was again added to the
updated mapping.
Also, add enabled setting to mapping always whenever enabled was set explicitely.

closes #8423
closes #8426
Parser throws NullPointerException when Filter aggregation clause is empty.
Added Junit test that recreates the error and fixed FilterParser to default to using a MatchAllDocsFilter if the requested filter clause is left empty.
Also added fix and test for the Filters (with an "s") aggregation.

Closes #8438
[STORE] Remove `memory`/ `ram` store

The RAM store is discuraged for production usage anyway and
we don't test it in our randomized infrastructure. This commit
removes it for `2.0`
Revert "[TEST] use logger level from test class annotation also in external nodes"

This reverts commit 4604a68bef9c54f5db812609157b18788279012d.
Remove NoneGateway, NoneGatewayAllocator, & NoneGatewayModule

Always use the LocalGateway* equivalents

We already check in the LocalGateway whether a node is a client node, or
is not master-eligible, and skip writing the state there. This allows us
to remove this code that was previously used only for tribe nodes (which
are not master eligible anyway and wouldn't write state) and in
tests (which can shake more bugs out)