Add remaining files

[podborski]

From the TuC:

• [HEIF] Conformance for the ‘prdi’ Item Property
• [HEIF] Conformance Samples for Region Items
• [HEIF] Conformance Samples for Region Tracks
• [ISOBMFF] Conformance for Essential Sample group
• [NALFF] Conforming files for picture-in-picture

From MPEG#143:

• http://mpeg.expert/software/MPEG/Systems/FileFormat/FFConformanceRefSoft/-/issues/35 (just software info. No conformance files in this one)
• http://mpeg.expert/software/MPEG/Systems/FileFormat/FFConformanceRefSoft/-/issues/31
• http://mpeg.expert/software/MPEG/Systems/FileFormat/FFConformanceRefSoft/-/issues/30 (waiting for FDIS to re-run gpac script and re-generate the most up to date versions. also pending mp4ra registration Code points for uncv mp4ra/mp4ra.github.io#168)
• http://mpeg.expert/software/MPEG/Systems/FileFormat/FFConformanceRefSoft/-/issues/29 (replaced by this one)
• http://mpeg.expert/software/MPEG/Systems/FileFormat/FFConformanceRefSoft/-/issues/28