Implement ST 0602.4 and ST 0602.5

[bradh]

What is the use case for your proposed feature? Please describe.
ST 0602 allows annotation of video with extra context. There is pretty limited use of that, but there is some.

Describe the solution you'd like
Implementation for reading and writing including display in the viewer.

Describe alternatives you've considered
We could just wait for a future annotation local set.

Additional context
There are extensions to 0602 used by other products. Incorporating those is out of scope for this request, but could be an interesting follow-up later.

[bradh]

Partly addressed in #337

[bradh]

While #337 has useful implementation, there are remaining tasks:

• Support preface elements (Lines Per Frame, Samples Per Line, Byte Order)
• Adequate test coverage for parsing and generating
• Support for Annotation Metadata Universal Set and items.
• Generate test data using CGM
• Generate test data using PNG
• Generate test data using JPEG
• Generate test data using BMP
• Generate test data that validates Z-Order.
• Generate realistic looking sample
• Add CGM annotation display support to viewer application
• Add PNG annotation display support to viewer application
• Add JPEG annotation display support to viewer application
• Add BMP annotation display support to viewer application
• Add Z-Order support for viewer application
• Update README.md
• Validate test data in CMITT
• Add convenience API for easy generation of annotations
• Add convenience API for easy consumption of annotations
• Add SVG to supported MIME types (per ST 0602.5)
• Add SVG rendering to viewer.

[bradh]

Work on Z-order and SVG at at #430