Add resolved parameters for Resource templates

[tvallin]

Fixes #32

This PR does not impact the API, but introduce new capabilities.

For the imperative way, templates parameters can be accessed from McpParameters class:

request -> {
          String name = request.parameters()
                  .get("name")
                  .asString()
                  .orElse("Unknown");
}

For declarative, parameter can be accessed from the method parameters:

@Mcp.Resource(
          uri = "https://{path}/foo",
          description = "Description",
          mediaType = MediaTypes.TEXT_PLAIN_VALUE)
String resource4(String path) {
    return path;
}

The examples and documentation have been also updated to reflect that change.