docs: xsl: newapi: Remove unused 'navbar' template

The template is unused since commit 9092c3d491

Remove also the up|right|left|home.png files which were only used by
code generated by the unused template.

Signed-off-by: Peter Krempa <pkrempa@redhat.com>
Reviewed-by: Ján Tomko <jtomko@redhat.com>

docs/html/meson.build

@@ -1,16 +1,3 @@
-apipng = [
-  'home.png',
-  'left.png',
-  'right.png',
-  'up.png',
-]
-
-install_data(apipng, install_dir: docs_html_dir / 'html')
-
-foreach file : apipng
-  install_web_files += '@0@:@1@'.format(meson.current_source_dir() / file, docs_html_dir / 'html')
-endforeach
-
 docs_html_gen = []
 docs_html_dep = []