Cleanups / Improvements to PSSH, KID, init data

[CastagnaIT]

Description

1. Reorganized code about PSSH parsing/generation to separate files

2. changed a bit InitializeDRM basically the same just changed order of variables, and following changes:

• if default KID missing can extract it from the (pssh) init data
• ExtractStreamProtectionData can extract also the default KID, where previously was used only when init data was missing
• ExtractStreamProtectionData has been limited to MP4, atoms used are MP4 should not works with other media types

3. to dashtree add missing parsing pssh for use case when ContentProtection pro is provided without cenc:pssh
4. add remaining missing pssh conversions to parsers, this allow to remove the code to convert init data (pssh) from widevine decrypters
5. add code to fix playready header data, this is an attempt to investigate to Playready problems of issue [Bug] PlayReady DRM dont works on android #1642.
   to make tests for example the DRM::FixPrHeader method can be added to DRM::PSSH::Make by checking that systemId is playready, part of this solution come from exoplayer https://github.com/google/ExoPlayer/blob/dd430f7053a1a3958deea3ead6a0565150c06bfc/library/core/src/main/java/com/google/android/exoplayer2/drm/FrameworkMediaDrm.java#L491-L496. In my tests i see changes on android logcat but dont work yet.

Motivation and context

another step to future drm rework

How has this been tested?

Screenshots (if appropriate):

Types of change

• Bug fix (non-breaking change which fixes an issue)
• Clean up (non-breaking change which removes non-working, unmaintained functionality)
• Improvement (non-breaking change which improves existing functionality)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that will cause existing functionality to change)
• Cosmetic change (non-breaking change that doesn't touch code)
• None of the above (please explain below)

Checklist:

• I have read the Contributing document
• My code follows the Code Guidelines of this project
• My change requires a change to the Wiki documentation
• I have updated the documentation accordingly