…r product testing, and more unit tests (elastic#48471)

* Adds stable alerting id's by using the alert params.
* Currently does a manual walk through of the alert params to find the stable id
* Updated all of the endpoints to take either of the two id's.
* Added several scripts to support performance testing ad-hoc such as `post_x_signals.sh`
* Added scripts to support converting from saved searches to alerts.
* Consolidated and fixed a lot of the backend types
* Added unit tests against the router endpoints
* elastic#47013

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~~- [ ] This was checked for cross-browser compatibility, [including a check against IE11](https://github.com/elastic/kibana/blob/master/CONTRIBUTING.md#cross-browser-compatibility)~~

~~- [ ] Any text added follows [EUI's writing guidelines](https://elastic.github.io/eui/#/guidelines/writing), uses sentence case text and includes [i18n support](https://github.com/elastic/kibana/blob/master/packages/kbn-i18n/README.md)~~

~~- [ ] [Documentation](https://github.com/elastic/kibana/blob/master/CONTRIBUTING.md#writing-documentation) was added for features that require explanation or tutorials~~

- [x] [Unit or functional tests](https://github.com/elastic/kibana/blob/master/CONTRIBUTING.md#cross-browser-compatibility) were updated or added to match the most common scenarios

~~- [ ] This was checked for [keyboard-only and screenreader accessibility](https://developer.mozilla.org/en-US/docs/Learn/Tools_and_testing/Cross_browser_testing/Accessibility#Accessibility_testing_checklist)~~

- [ ] This was checked for breaking API changes and was [labeled appropriately](https://github.com/elastic/kibana/blob/master/CONTRIBUTING.md#release-notes-process)
- [ ] This includes a feature addition or change that requires a release note and was [labeled appropriately](https://github.com/elastic/kibana/blob/master/CONTRIBUTING.md#release-notes-process)