chore: add legacy project templates

[Tsvetomir-Hr]

Related to: https://github.com/telerik/blazor/issues/9904

[dimodi]

• Add a README.md file in the legacy with an explanation what these apps are.
• Do we really need both server and WASM options for all apps? If there is no unique / different code for each hosting model, we can go with just one option. The goal is to show how to implement the Telerik-specific stuff, which usually does not depend on the hosting model.

[Tsvetomir-Hr]

• Do we really need both server and WASM options for all apps? If there is no unique / different code for each hosting model, we can go with just one option. The goal is to show how to implement the Telerik-specific stuff, which usually does not depend on the hosting model.

How do we decide which hosting model to retain? If we keep only the Server hosting model, some clients will request the WASM example, and vice versa. I think the main intent behind transferring the source code from the vsx-templates to the blazor-ui repo is to retain the visibility and continued access.

[radkostanev]

adding a README file explaining what these are is certainly a nice addition.

As for what hosting models to retain - I'd suggest simply moving these now as-is, and only if demand requires it, we may think of spending more time refactoring them.