JUCE 8 Update

[jthorborg]

Signalizer is currently built on a custom version of JUCE 4. This PR instead versions JUCE as a submodule, referenced from its source location here on github, hoping no custom fixes are necessary anyway.

There has been a lot of interest in a native arm build, so this is the primary motivation beyond HiDPI scaling on Windows.

• Non-modal file selectors
• Fixing edit spaces jasserting when capturing keyboard focus
• Edit spaces have become rounded instead of squared
• Peer popups do not respect primary scale factor
• Direct2D renderer does not employ subpixel text rendering (see Direct2D: Add ClearType Antialiasing back to D2D as a module option juce-framework/JUCE#1610)
• Edit spaces do not terminate after animating application
• Full screen kiosk not exiting properly
• Kiosk ignoring DPI scaling
• Graphics flood fill solution for non-integer DPI scaling modes
• 2D graphics clipping performance regression in OpenGL views
• Profiling comparisons for regressions
• Windows D2D text renderer font clipping (especially "spectrum stretch" and x/y/z on transforms)
• Windows VST3 testing
• Update windows release build scripts
• Update macOS release build scripts
• Update ubuntu release build scripts Ubuntu24 LTS juce update #5
• macOS testing, 10.13
• macOS testing, 10.15+
• Ubuntu testing 24 lts
• Version bump

• Profiling comparisons for regressions

Generally, looks to be a 40% hit. The driver code is structured differently in JUCE so it's difficult to directly compare where time is being spent.

The shared code sections of Signalizer with other plugins is developed in tandem here: jthorborg/cpl#3