fix(*): moving the IgxOverlayOutletDirective and some renamed exports and fixing migration

[kdinev]

Closes #

Additional information (check all that apply):

• Bug fix
• New functionality
• Documentation
• Demos
• CI/CD
• Refactoring

Checklist:

• All relevant tags have been applied to this PR
• This PR includes unit tests covering all the new code (test guidelines)
• This PR includes API docs for newly added methods/properties (api docs guidelines)
• This PR includes feature/README.MD updates for the feature docs
• This PR includes general feature table updates in the root README.MD
• This PR includes CHANGELOG.MD updates for newly added functionality
• This PR contains breaking changes
• This PR includes ng update migrations for the breaking changes (migrations guidelines)
• This PR includes behavioral changes and the feature specification has been updated with them

[damyanpetev]

@copilot Can you refactor the custom migration logic behind the shouldMigrateImports into a separate migration (leaving us with two migrations for version 21.0.0) since the schema is not working/supported on migrations and it should use a separate entry in the collection json with optional: true flag to achieve the prompt instead.
See https://github.com/angular/angular-cli/blob/36cf3afb485a01f86c4c90f136b38a3cf338e313/packages/schematics/angular/migrations/migration-collection.json#L8 for reference.

[Copilot]

@damyanpetev I've opened a new pull request, #16511, to work on those changes. Once the pull request is ready, I'll request review from you.