This PR upgrades RxJS to version 6 and switches to a fork of `stream-to-observable` which includes an updated version of `any-observable` that supports RxJS 6 until https://github.com/jamestalmage/stream-to-observable/pull/10 is merged. The primary change in this version of RxJS is the movement of stream operators from `Obersable.prototype` to the `rxjs/operators` module. Some of the operators, like `catch` and `do`, have been renamed (`catchError`, and `tap`). The Obsevable factories have also been moved from static methods on the `Observable` class to named exports of the root `rxjs` module. Some of those factories have also changed slightly, like `fromEvent` which now emits arrays if the event handler is called with multiple arguments.
```js
// import the Rx namespace to get the Observable factories
import * as Rx from 'rxjs';
// import the operators as named imports
import { map, tap, switchMap } from 'rxjs/operators';
```
In order to make the license that applies to each file as clear as possible, and to be consistent with elasticsearch, we are adding Apache 2.0 license headers to the top of each file.
Existence of this header is enforced by eslint and tslint and missing headers were automatically added in the last commit by running:
```
node scripts/eslint --fix && node scripts/tslint --fix
```
* Revert "[DOCS] Removes redundant index.asciidoc files (#19192)"
This reverts commit d11b5aae9a.
* Revert "[typescript] add typescript support for the server and browser (#19104)"
This reverts commit c6112067fc.
* Revert "Option to run kibana from build for CI (#19125)"
This reverts commit 5969860303.
Restructure testing with kbn-test package
- Run with multiple configs, move cli options to config
- Package-ify kbn-test
- Eventually we'll have functional_test_runner live in a package
of its own, and then this kbn-test will use that as a dependency,
probably still as a devDependency.
- Implement functional_tests_server
- Collapse single and multiple config apis into one command
Use kbn-es
Replace es_test_cluster + es_test_config with kbn/test utils
Implement new createEsTestCluster
Improve scripts, jsdocs, cli top-level tools
Lift error handling to the top level
