parse unity version hash code (changeset) from data files

[unitycoder]

this file contains hash code
Editor\Data\PlaybackEngines\windowsstandalonesupport\Source\WindowsPlayer\WindowsPlayer\UnityConfigureRevision.gen.h

this hash can be then used for downloading more platforms (without starting unity and going into build settings), with direct links like:
http://beta.unity3d.com/download/7e2ed8c1221a/TargetSupportInstaller/UnitySetup-Universal-Windows-Platform-Support-for-Editor-2020.1.0b4.exe
http://beta.unity3d.com/download/7e2ed8c1221a/TargetSupportInstaller/UnitySetup-WebGL-Support-for-Editor-2020.1.0b4.exe

• its also available per project, at: ProjectSettings/ProjectVersion.txt
• visible on unity.exe productVersion

todo

• parse code only when needed (not at start)
• add option to download platform installer for selected unity version, but how/where?
• build download link from hash, unity version, selected platform installer

[unitycoder]

not available in latest unity versions, like 2022.1.0b2
there is "UnityConfiguration.gen.cpp" but different contents..

[unitycoder]

now checks unity.exe productVersion first, its available for 2018.4 and later