Add support for fixed-rate compression extensions

Add support for multiple extensions related to fixed-rate framebuffer compression:

• GL_EXT_texture_storage_compression: enables applications to opt-in to compression for immutable textures.
• EGL_EXT_surface_compression: enables applications to opt-in to fixed-rate compression for EGL window surfaces.
• GL_EXT_EGL_image_storage_compression: enables applications to specify a texture by taking all properties from a fixed-rate compressed EGLImage.

Gallium drivers that want to enable these extensions need to implement the following hooks:

• query_compression_rates
• query_compression_modifiers
• is_compression_modifier

A good chunk of this merge request are patches to use PIPE_ pixel formats everywhere to make it easier to get format-specific information (supported compression rates and modifiers) through the different layers without having to translate the format