Refactor the Features to include more portability flags

[kvark]

We've reached the limit of u64 bitflags for the Features. We should leave the Vulkan proper flags there, but move all the extra stuff into a separate bitflags/struct. Here are the new flags we need:

    //TODO: add a feature for non-normalized samplers
    //TODO: add a feature for mutable comparison samplers

[betoissues]

More or less something like ExtraFeatures. An example of those "extra" features from what I've read on the spec would be:

        /// Support triangle fan primitive topology.
        const TRIANGLE_FAN = 0x1000_0000_0000_0000;
        /// Support separate stencil reference values for front and back sides.
        const SEPARATE_STENCIL_REF_VALUES = 0x2000_0000_0000_0000;
        /// Support manually specified vertex attribute rates (divisors).
        const INSTANCE_RATE = 0x4000_0000_0000_0000;
        /// Support non-zero mipmap bias on samplers.
        const SAMPLER_MIP_LOD_BIAS = 0x8000_0000_0000_0000;