* [ci/es] base default es version on pkg.branch value
* [ci/env] initialize $TEST_ES_FROM in checkout_sibling_es.sh
* [UA] remove TEST_ES_SNAPSHOT_VERSION override
* [ci/es] call checkout_sibling_es.sh from one location
* [ci] remove unused `--from` param
* [ci/env] always default to snapshots, switch to source when necessary
* [kbn/test] default esFrom to $TEST_ES_FROM
* [ci/setup] fix define order
* [ci/grunt] don't pass --esFrom let env pass through
* [ci/env] use branch, not version
* [ci] use same indent style as following lines
* [kbn/test] apply default values when processing args
* [kbn/test] simplify defaults, read default on each process
* [ci][ftr][kbn/test] split up CI jobs
* [ci] run --assert-none-excluded in ci groups, before builds
* [ftr] improve error message when excluded tests found
* [ci] document other places the ciGroups live
