We are relying on the fact that :x-pack-elasticsearch:plugin:core is
configured before these. This happens when these projects are
alphabetically after core, but is not the case when they are not
(ccr). To address this, we simplfy be explicit about evaluation order in
all sub-plugins.
Relates elastic/x-pack-elasticsearch#3663
Original commit: elastic/x-pack-elasticsearch@755f84258b
* Rename folder x-pack-core -> core
The jar remains 'x-pack-core-*.jar'
* Put group in top-level build.gradle instead of plugin/core/build.gradle
Original commit: elastic/x-pack-elasticsearch@b23452fa55
This creates a basic skeleton for the plugin split by adding folders and example
`build.gradle` files. It also includes a non-implemented `migrate-plugins.sh`
script that we can fill in at a later time.
Relates to elastic/x-pack-elasticsearch#2925
Original commit: elastic/x-pack-elasticsearch@2ab035d6b6