Clean up old PowerShell code #130

Job	Run time
Run Pre-Checks	3s
Build FFmpeg (macos-arm64)	5m 27s
Build FFmpeg (macos-x86_64)	5m 2s
Build FFmpeg (linux-x86_64)	1m 15s
Build FFmpeg (windows-x64)	5m 6s
Build FFmpeg (windows-x86)	3m 1s
Build Qt6 (macOS)	9m 57s
Build Windows Dependencies (x64)	3m 57s
Build Windows Dependencies (x86)	2m 39s
Build macOS Dependencies (macos-arm64)	5m 42s
Build macOS Dependencies (macos-x86_64)	5m 5s
Build Qt6 (Windows) (x64, RelWithDebInfo)	3m 32s
Build Qt6 (Windows) (x64, Debug)	4m 46s
Build Qt6 (Windows) (x86, RelWithDebInfo)	3m 28s
Build Qt6 (Windows) (x86, Debug)	5m 31s
Build FFmpeg (Universal)	7s
Build macOS Dependencies (Universal)	5s
Package Windows Qt6 (x64)	9s
Package Windows Qt6 (x86)	14s
Create macOS Qt6 (macos-arm64)	6s
Create macOS Qt6 (macos-x86_64)	4s
Create and upload release	0s
	1h 5m 16s

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