This commit changes the default out-of-the-box configuration for the
number of shards from five to one. We think this will help address a
common problem of oversharding. For users with time-based indices that
need a different default, this can be managed with index templates. For
users with non-time-based indices that find they need to re-shard with
the shrink API in place they no longer need to resort only to
reindexing.

Since this has the impact of changing the default number of shards used
in REST tests, we want to ensure that we still have coverage for issues
that could arise from multiple shards. As such, we randomize (rarely)
the default number of shards in REST tests to two. This is managed via a
global index template. However, some tests check the templates that are
in the cluster state during the test. Since this template is randomly
there, we need a way for tests to skip adding the template used to set
the number of shards to two. For this we add the default_shards feature
skip. To avoid having to write our docs in a complicated way because
sometimes they might be behind one shard, and sometimes they might be
behind two shards we apply the default_shards feature skip to all docs
tests. That is, these tests will always run with the default number of
shards (one).

This commit fixes a few issues in the REST client tests that arose from
moving to one shard. Moving to one shard causes a reordering of
calculations which impacts floating-point arithmetic. It can also impact
scoring and thus the ranking of docs.

This commit fixes a SQL test with security that was expecting five
shards.

Let us just hard code the test to always use one shard, it is easier
that way.

* master:
  Deprecate not copy settings and explicitly disallow (elastic#30404)
  [ML] Improve state persistence log message
  Build: Add mavenPlugin cluster configuration method (elastic#30541)
  Re-enable FlushIT tests
  Bump Gradle heap to 2 GB (elastic#30535)
  SQL: Use request flavored methods in tests (elastic#30345)

* master:
  Adjust copy settings versions
  Mute ShrinkIndexIT suite
  SQL: SYS TABLES ordered according to *DBC specs (elastic#30530)

…them-all

* elastic/master:
  Add missing dependencies on testClasses (elastic#30527)
  [TEST] Mute ML test that needs updating to following ml-cpp changes
  Document woes between auto-expand-replicas and allocation filtering (elastic#30531)
  Moved tokenizers to analysis common module (elastic#30538)