Font Engine refactor and features

[wouterlucas]

Creating a collection of tickets / changes / features to refactor the Font Engines.

Note might not cover all requested features, however this ticket is raised as a tracker for "what needs to be done" for Text at this stage.

Issues / open PRs:

• SDF Font Engine buffer refactor: SDF text rendering buffer refactor #466
• Wrong wrapping: Wrong wrapping with contain width and text too long #268
• Wrap word PR: Implement wrapWord parameter (#268) #345
• Last trailing space Last trailing space seems to be trimmed from a text string #478
• Text node width incorrect Width of text node with word wrapping not correct when text is smaller than word wrapping width #455 (might be linked to Last trailing space seems to be trimmed from a text string #478)
• SDF Text layout refactor: SDF Text Layout Refactor #223

Features:

• Text Baseline Implement 'textBaseline' SDF property #134 and Text Rendering - Oversized Canvases - Baseline and Vertical Positioning #382
• RTL Text support: 🌍 Add RTL Text Support for Canvas and SDF Font Renderers (Arabic, Hebrew, etc.) #475
• Global font scaling: Global Font Scaling #161
• Underlike / strikethrough support: Add underline / strikethrough support for SDF text #464
• Span support: Span for Text element #269
• Dropshadow on Text: Drop shadows #23
• Multi page / scrolling Canvas text: Multi-Page Canvas 2D Text #321

Closing #322 as a result of upcoming changes to the Text Renderer, mainly:

• Reduction of variable assignments (excessive const usage) to lower GC pressure
• Removal of intermediate TrState duplication
• Single SDF Buffer handling to reduce SDF text rendering buffer refactor #466
• Single Canvas Text generation function and node to texture assignment for Canvas Text. Goal would be get closer to L2 Canvas Text performance