[Feature]: Expand GStreamer video support for more codecs and pixel formats

Short Description

Broaden GStreamer-based video I/O to support more codecs and raw pixel formats beyond the current limited set.

Motivation

The current GStreamer path appears to support only a narrow codec/format matrix. That limits usefulness for real-world video pipelines, where users may need different encoders, containers, and raw pixel formats depending on their hardware, plugins, and workflow.

Proposed Solution

• Extend codec handling in VideoWriter.
• Extend raw pixel format support in both VideoWriter and VideoReader.
• Replace hardcoded limitations with clearer validated mappings where possible.
• Improve error messages for unsupported combinations.
• Add tests and documentation for the supported matrix.

Expected Outcome

kornia-io becomes more practical for real video workflows by supporting a broader, clearly documented set of codecs and pixel formats.

✅ Acceptance Criteria

• At least one additional codec path is supported or the supported set is clearly documented.
• Additional raw pixel formats are supported in writer and/or reader paths.
• Unsupported combinations return clear errors.
• Tests and docs cover the supported combinations.

Additional Context

This issue is about GStreamer-based video functionality and should be reviewed separately from still-image format support in functional.rs.

Code Reference

// crates/kornia-io/src/gstreamer/video.rs ~59, ~70, ~246
// TODO: Add support for other codecs
// TODO: Add support for other formats
// TODO: Support more formats

🤝 Contribution Intent

• I plan to submit a PR to implement this feature
• I'm requesting this feature but not planning to implement it