Core: Support parameters.__id and metaId in indexers

[JReinhold]

Works on #23457

What I did

1. This PR changes the IndexInput:
   1. rename key to exportName
   2. Add support for metaId, to optionally overwrite the automatic generation of meta id based on title. If this is passed by the indexer, it must also be set at meta.id to be picked up by the preview too. CsfFile.parse() already does all of this.
   3. Add support for __id, to optionally overwrite the automatic generation of the whole story id. If this is passed by the indexer, it must also be set at story.parameters.__id to be picked up by the preview too.
2. Adds support for story.parameters.__id in CsfFile.parse(). If this is set now, the story will pick that up as the its id, disregarding anything else.

How to test

See new unit tests for CsfFIle, as well as the updated ones with the IndexInput changes. I've also added some stories that tests the custom id, that should show up in Chromatic.

Checklist

• Make sure your changes are tested (stories and/or unit, integration, or end-to-end tests)
• Make sure to add/update documentation regarding your changes
• If you are deprecating/removing a feature, make sure to update
  MIGRATION.MD

Maintainers

• When this PR is ready for testing, make sure to add ci:normal, ci:merged or ci:daily GH label to it to run a specific set of sandboxes. The particular set of sandboxes can be found in code/lib/cli/src/sandbox-templates.ts
• Make sure this PR contains one of the labels below.

["cleanup", "BREAKING CHANGE", "feature request", "bug", "build", "documentation", "maintenance", "dependencies", "other"]

🦋 Canary release

This PR does not have a canary release associated. You can request a canary release of this pull request by mentioning the @storybookjs/core team here.

core team members can create a canary release here or locally with gh workflow run --repo storybookjs/storybook canary-release-pr.yml --field pr=<PR_NUMBER>

[shilman]

LGTM! This still all seems a little more convoluted than it could be, but I don't have any suggestions