Support multiple sps/pps/vps in h265 AU

[JoTurk]

Description

As discussed in discord, the SkipAggregation behavior isn't correct for H265 because streams can have multiple sps/pps/vps with different ids. while I wasn't able to find any non-svc real media files with this it's correct in the spec and chrome can play even tho chrome doesn't support SHVC http://download.tsi.telecom-paristech.fr/gpac/MPEG/LHEVCFF/Conformance/shvc_hev1_single_track.mp4 it's able to play this file after the fix (tested with hardware decode NVENC).
The problem is that the order in this file is:

#id=0  VPS
#id=0  SPS  
#id=0  PPS
#id=1  SPS  
#id=1  PPS
#id=0  IDR 
#id=1  IDR

chrome picks layer #0 and because we cache the last SPS/PPS the file doesn't play before this fix. I'm not sure if we should merge this as this sounds like a niche with more complexity trade off but it might become more common with svc h265 or other uses and it can save someone a few hours of debug in the future.
This is only a draft because i didn't add tests yet

[codecov]

Codecov Report

❌ Patch coverage is 94.63087% with 8 lines in your changes missing coverage. Please review.
✅ Project coverage is 82.19%. Comparing base (2b19d5b) to head (378032e).

Files with missing lines	Patch %	Lines
codecs/h265_packet.go	94.63%	4 Missing and 4 partials ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #366      +/-   ##
==========================================
+ Coverage   81.76%   82.19%   +0.42%     
==========================================
  Files          28       28              
  Lines        3526     3656     +130     
==========================================
+ Hits         2883     3005     +122     
- Misses        453      457       +4     
- Partials      190      194       +4     

Flag	Coverage Δ
go	82.19% <94.63%> (+0.42%)	⬆️

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[Ibn-Butt-Toota]

Maybe we can create a section in the readme to document spec-breaking implementations or conflicts like this so it can be easier for observers to find? Or maybe if it's feasible we could add an experimental flag...

[JoTurk]

@Ibn-Butt-Toota thank you for the review, this is the spec correct way to cache sps/pps/vps the problem is that it's not clear if multiple sps/pps/vps are used outside of shvc and if it's common :)

[Ibn-Butt-Toota]

Sorry I misread the main comment. Thank you for clarifying. The PR still looks good (I know it's pending tests still).

[Sean-Der]

oh hell yea, thank you for fixing this @JoTurk !

[JoTurk]

@Sean-Der thank you for the review <3 turned out there were many other edge cases with multiple sps/pps/vps idk why h265 is this complex, hopefully I handled all of them :)