Db examples should use reactive approach (including template for CLI)

[tomas-langer]

Current code:

try {
            List<PokemonType> pokemonTypes =
                    dbClient.execute(exec -> exec.namedQuery("select-all-types"))
                            .map(row -> row.as(PokemonType.class)).collectList().get();
            response.send(pokemonTypes);
        } catch (InterruptedException | ExecutionException e) {
            throw new RuntimeException(e);
        }

Correct code:

dbClient.execute(exec -> exec.namedQuery("select-all-types"))
                .map(row -> row.as(PokemonType.class))
                .collectList()
                .forSingle(response::send);

This is valid for other methods as well - we should never ever call .get on a completable future or await on Single or Multi in a routing method of web server