Implement support for EXT_sRGB_write_control. This extension
requires VK_KHR_image_format_list to be supported.

The spec requires this functionality to work with glBlitFramebuffer
as well but support for that will be added in a follow up change.
As such, this extension is only exposed in non-conformant mode.

Bug: angleproject:5075
Tests: SRGBFramebufferTest.*Vulkan*
Change-Id: I59b38f6cd810a3d0d67ec29f4f19c25f65f70862
Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/2617243
Commit-Queue: Mohan Maiya <m.maiya@samsung.com>
Reviewed-by: Jamie Madill <jmadill@chromium.org>
Reviewed-by: Shahbaz Youssefi <syoussefi@chromium.org>