Add support for fog, toneMapping, colorSpace conversion and logarithmicDepthBuffer to (m)sdf shaders

[mrxz]

Description:
Changes both sdf and msdf shaders to make use of relevant Three.js ShaderChunks. This makes it behave more like other Three.js materials, resolving several outstanding issues:

• Color management (and tone mapping): Msdf font have a bad color space since update to v1.5.0 #5408
• Logarithmic depth buffer: Text not rendering when logarithmicDepthBuffer is enabled #4279
• Fog: Scene fog not working on a-text #4261

Changes proposed:

• Change shaders to non-raw shaders including relevant chunks for: fog, logdepthbuf, tonemapping and colorspace
• Remove WebGL1 code paths from the sdf shader

[dmarcos]

Thank you!