Retrieve content by ID, inode, query, or related content

Retrieves contentlets using various lookup strategies. Parameters use a slash-delimited key:value format in the URL path (e.g., /api/content/inode:abc123/live:true/language:1). Supported parameters include: id (identifier), inode, query (Lucene query), type (json or xml), orderby, limit, offset, language, live, depth (0-3 for relationship traversal), render (true to render widgets), related (ContentType.Field:identifier format), and allCategoriesInfo. When 'depth' is set: 0 returns related content identifiers, 1 returns full related content objects, 2 returns related content with their related identifiers, 3 returns related content with their fully hydrated related content.