improved representation of descendant items in item view

[vitorgomateus]

• sorted formats with a list passed through render_template
• sorted items within formats by identifier using jinja sort()
• reduced each item size
• replaced “item has conversions” icon with just a plus icon
• converted item names to h3
• Labeled only first second generations with an h2, further generations are distinguished only by visual indentation.
• removed not original formats from series view