[PATCH v4 0/5] MR7570: mfreadwrite: Implement encoder creation. (Part 1)

[Ziqing Hui (＠zhui)]

I split the implementations into 2 parts to make it looks easier to review. So plz first review this MR and make sure it's good so that we don't have to rebase. The follwing patches is in !7571.

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  v4: mfreadwrite/tests: Test getting transform for a writer without converter.
      mfreadwrite: Implement sink_writer_SetInputMediaType.
      mfreadwrite: Implement IMFSinkWriterEx.
      mfreadwrite: Add converter transform to stream.
      mfreadwrite: Add attributes member to writer struct.
 
https://gitlab.winehq.org/wine/wine/-/merge_requests/7570