meandco on "Use Categories In A Page Template"

Hello. I'm wondering if anyone can help.

What I want to do is show specific categories ina page template.
For example:

<!-- START LOOP -->
        <?php query_posts('category_name=catname'); ?>
        <?php if (have_posts()): while (have_posts()) : the_post(); ?>

        <div class="col-sm-6 col-md-4 contentBlock">
        <div class="thumbnail"><?php the_post_thumbnail('featured-image'); ?>
        <div class="caption">
                <h3><?php the_title(); ?></h3>
                <p><?php the_excerpt(); ?></p>

        <div id="edit"><?php edit_post_link(); ?></div>

        </div><!--/CAPTION -->
        <div class="col-9 btnArrowBlack"><p><a href="#">More</a></p></div>
        </div><!--/THUMBNAIL -->
        </div><!--/COL -->

        <?php endwhile; else: ?>
        <p><?php _e('Sorry, no posts matched your criteria.'); ?></p>

        <?php endif; ?>
        <!-- END LOOP -->

And this mixes in with my styles fine.
So I have that in the template and it shows all posts from that category in the page template.

What I don't want to do is have to create a new template and put in the new cat id or slug everytime I want a new page.

I just want to create a page based on one page template and show the categories.

Can anyone help and hopefully this make sense?

Thank you in advance, I will reply.