feat: reimplement @RouteScoped to keep beans for PreserveOnRefresh

[denis-anisimov]

• presere beans for PreserveOnRefresh views
• reimplement absent RouteScopeOwner semantic
• do not allow to use (route) scope when it's not available

fixes #369

Description

Please list all relevant dependencies in this section and provide summary of the change, motivation and context.

Fixes # (issue)

Type of change

• Bugfix
• Feature

Checklist

• I have read the contribution guide: https://vaadin.com/docs/latest/guide/contributing/overview/
• I have added a description following the guideline.
• The issue is created in the corresponding repository and I have referenced it.
• I have added tests to ensure my change is effective and works as intended.
• New and existing tests are passing locally with my change.
• I have performed self-review and corrected misspellings.

Additional for Feature type of change

• Enhancement / new feature was discussed in a corresponding GitHub issue and Acceptance Criteria were created.

[pleku]

Let's merge #371 before this though so we get a correct snapshot version