Several depth and color formats have been added for the framebuffer.

8-bit, 16-bit, and 24-bit formats are now available for depth.

RGB 8-bit (332), RGB 16-bit (565), and RGB 24-bit (888) formats are now available for color.

Alpha support is no longer present for the framebuffer at the moment, but it can easily be restored by adding the formats and reinterpolating the alpha in the areas that do not perform color blending.

Additionally, this commit brings performance improvements.

+ review unorm/float conversion

to be closer to the OpenGL API

+ tweak function names

Also replace the triangle rasterization functions with macros that generate specific functions for each state of the rendering system.
Also, add the OpenGL definitions in order to add a binding for rlgl.

[rcore] sinfl_bsr fix for TCC

* update RGFW to 1.6

* properly handle RGFW_quit events

* fix rcore_desktop_rgfw bugs

* update

* update

* uncomment out

* Reorganize some conditions to fix overlap bugs

* Fix edge case where control point selection outlives mouse down

Previous runner `ubuntu-20.04` is deprecated and being removed soon: https://github.com/actions/runner-images/issues/11101

...so it will always prioritize local version of raylib instead of
system-wide installations, which is a huge problem when testing any
changes done locally to raylib as it might cause silent mismatch issues.
There were only 4 examples affected by this issue which were using
`#include <raylib.h>`. Other examples use proper `#include "raylib.h"`

Fixes: https://github.com/raysan5/raylib/issues/4820

* [rcore] fix crash in InitWindow, due to unchecked result of InitPlatform

Check the result of InitPlatform(), if it isn't 0, report the Error
and return. This prevent crashes and allows for gracefully aborting
or recovering by checking IsWindowReady().

Partially-fixes: https://github.com/raysan5/raylib/issues/4801

* [rcore] style: store the result of InitPlatform() before checking it

Small style change that doesn't impact how the code behaves here.
Variable 'result' is not used anywhere else in this block,
it's just for compliance with Raylib's coding conventions.

Requested in PR: https://github.com/raysan5/raylib/pull/4803#discussion_r1976502788

* [rcore] use LOG_WARNING when InitPlatform() fails

...as this is preferred over LOG_ERROR.

Requested-by: https://github.com/raysan5/raylib/pull/4803#discussion_r1976651724

...returning NULL. This was causing a crash few lines later.

Refs: https://github.com/raysan5/raylib/issues/4801#issuecomment-2691201072
Partially-fixes: https://github.com/raysan5/raylib/issues/4801

* search raylib in custom directory

* avoid loading dynamic library when both are installed

* raylib_USE_STATIC_LIBS as option ON