Split Pattern classes into separate files

[Spekular]

Part of #5592

[LmmsBot]

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Windows

• Windows 64-bit: lmms-1.3.0-alpha.1.98%2Bg43f2608ff-mingw-win64.exe (build link)
• Windows 32-bit: lmms-1.3.0-alpha.1.98%2Bg43f2608ff-mingw-win32.exe (build link)
• Windows 32-bit: lmms-1.3.0-alpha-msvc2017-win32.exe (build link)
• Windows 64-bit: lmms-1.3.0-alpha-msvc2017-win64.exe (build link)

Linux

• Linux (AppImage): lmms-1.3.0-alpha.1.98%2Bg43f2608-linux-x86_64.AppImage (build link)

🤖

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