Remove combined/convenience image_usage flags

[johannesugb]

...because we're going back to being explicit and more true to raw Vulkan.

Therefore, remove all of the following:

		/** General image usage that can be used for transfer and be sampled, stored in an efficient `tiling_optimal` format. */
		general_image							= transfer_source | transfer_destination | sampled | tiling_optimal,

		/** An image that shall only be used in readonly-mode. */
		read_only_image							= transfer_source | sampled | read_only | tiling_optimal,

		/** An image with the same properties as `general_image` and in addition, can be used for shader storage operations */
		general_storage_image					= general_image | shader_storage, 

		/** An image with the same properties as `general_image` with the `read_only` flag set in addition. */
		general_read_only_image					= general_image | read_only,

		/** A `general_image` intended to be used as a color attachment. */
		general_color_attachment				= general_image | color_attachment,

		/** A color attachment used in read only manner. */
		read_only_color_attachment				= read_only_image | color_attachment,

		/** A `general_image` intended to be used as a depth/stencil attachment. */
		general_depth_stencil_attachment		= general_image | depth_stencil_attachment,

		/** A depth/stencil attachment used in read only manner. */
		read_only_depth_stencil_attachment		= read_only_image | depth_stencil_attachment,

		/** A `general_image` intended to be used as input attachment. */
		general_input_attachment				= general_image | input_attachment,

		/** An input attachment used in read only manner. */
		read_only_input_attachment				= read_only_image | input_attachment,

		/** A `general_image` intended to be used as shading rate image */
		general_shading_rate_image				= general_image | shading_rate_image,

		/** A `general_image` intended to be used as texture and has MIP mapping enabled by default. */
		general_texture							= general_image | mip_mapped,

		/** A `general_texture` intended to be used as cube map. */
		general_cube_map_texture				= general_texture | cube_compatible,