Add opengl_rtt example.

[hellozyemlya]

• wraps parameters of CanvasRunner to struct, just in case more rendering information will be passed in future
• adds simple opengl_rtt example:
  • messing with raw opengl to render triangle
  • renders to texture
  • using raw opengl texture to draw on skia canvas

[codecov]

Codecov Report

Attention: Patch coverage is 0% with 88 lines in your changes missing coverage. Please review.

Project coverage is 73.79%. Comparing base (de6d87c) to head (c8684d8).
Report is 2 commits behind head on main.

Files	Patch %	Lines
crates/components/src/graph.rs	0.00%	81 Missing ⚠️
crates/core/src/elements/rect.rs	0.00%	7 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #813      +/-   ##
==========================================
- Coverage   73.81%   73.79%   -0.03%     
==========================================
  Files         201      201              
  Lines       21530    21537       +7     
==========================================
  Hits        15893    15893              
- Misses       5637     5644       +7     

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[marc2332]

The code looks nice! I'll try it asap. Nice work! and sorry for the delay