feat(ui): draw ui through commands

[DiogoMendonc-a]

Description

The two main UI components are UIElement and UICanvas. For it to work properly, each UIElement must be a child of a UICanvas, or of another UIElement.

Each UIElement generates a list of drawing commands, UIDrawList, that are then pooled together by the UICanvas at the root of the hierarchy.

Each entry in a draw list contains a UIDrawList::Type and a UIDrawList::Command. The Type holds information that is common for all similar commands, and the Command contains the specifics to that one command. Each entry also has a raw data buffer to hold the data the command needs to pass to the shaders.

After aggregating the draw commands, the UICanvas draws them, grouped by type.

Checklist

• [ ] Self-review changes.
• [ ] Evaluate impact on the documentation.
• [ ] Ensure test coverage.
• [ ] Write new samples.
• [x] Add entry to the changelog's unreleased section. No need, this is altering stuff that will be added this version

[github-actions[bot]]

PR Preview Action v1.4.7 :---: :rocket: Deployed preview to https://GameDevTecnico.github.io/cubos/docs-preview/pr-1189/ on branch gh-pages at 2024-05-26 11:43 UTC

[codecov[bot]]

Codecov Report

Attention: Patch coverage is 0% with 143 lines in your changes are missing coverage. Please review.

Project coverage is 40.37%. Comparing base (1d9683b) to head (81cb2f5).

Files	Patch %	Lines
engine/src/ui/canvas/draw_list.cpp	0.00%	63 Missing :warning:
engine/src/ui/canvas/plugin.cpp	0.00%	63 Missing :warning:
engine/src/ui/color_rect/plugin.cpp	0.00%	12 Missing :warning:
engine/include/cubos/engine/ui/canvas/element.hpp	0.00%	2 Missing :warning:
engine/src/ui/canvas/element.cpp	0.00%	2 Missing :warning:
core/include/cubos/core/ecs/query/opt.hpp	0.00%	1 Missing :warning:

Additional details and impacted files

```diff @@ Coverage Diff @@ ## main #1189 +/- ## ========================================== - Coverage 40.53% 40.37% -0.16% ========================================== Files 349 351 +2 Lines 25925 26030 +105 ========================================== + Hits 10508 10509 +1 - Misses 15417 15521 +104 ```

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[RiscadoA]

Feel free to merge @DiogoMendonc-a! The CI is failing but it isn't your fault; lets hope it starts working on other PRs.