Add Vaadin metadata to GraalVM Reachability Repository

[mshabarov]

Describe your motivation

Native Image builds only include elements directly reachable from the entry point, libraries, and JDK classes. Dynamic features like reflection and proxies may leave some elements undiscovered, causing runtime issues. Thus, Native Image requires a metadata from Vaadin to make it ready for Native compilation.

Describe the solution you'd like

Provide Vaadin reachability data and commit it to GraalVM Reachability Metadata Repository.

See also Reachability Metadata docs for more details.

Describe alternatives you've considered

Provide reachability metadata as part of Vaadin JARs, this is the best way, but I don't know what is easier.

Additional context

Target release is 24.6.