Fixes#6552Fixes#6910Fixes#6872
Implementation of new node design. Includes many changes related to stylesheet update handling and per-style FRP construction, as well as refactoring of scene layers used by graph editor. Some additional components were migrated to use `Rectangle` shape and new mouse handling events. Fixed text rendering, where random thin lines appeared at the borders of glyph sprites. Refined edge layout to match new node sizes and not leave any visible gaps between line segments.
The node colors are currently randomly selected from predefined list. Later this will be improved to use group information from the suggestion database, once that is fully migrated to use the documentation tags, thus removing the dependency on the execution context.
https://github.com/enso-org/enso/assets/919491/aa687e53-a2fa-4e95-a15f-132c05e6337a
<img width="653" alt="image" src="https://github.com/enso-org/enso/assets/919491/30f3e897-62fc-40ea-b57b-124ac923bafd">
Fixes https://www.pivotaltracker.com/story/show/184216698
Reduced impact of node dropdown widgets on load times by deferring creation of grid views until each widget is opened. This also improves node editing time, as the dropdowns are not recreated immediately.
This approach of lazy initialization now caused a significant lag when opening the dropdown. Two major causes of the lag spike is glyph generation (msdfgen, `new_glyph`) and shader compilation (happened every time, because each dropdown has unique layer stack). To reduce the impact of that, the shader compiler now caches the shaders based on generated shader source. Glyph creation hasn't been changed and is still slow. The startup performance is now roughly where it was before introducing widgets.
