vk_device: Add miscellaneous features and minor style changes

* Increase minimum Vulkan requirements
* Require VK_EXT_vertex_attribute_divisor
* Require depthClamp, samplerAnisotropy and largePoints features
* Search and expose VK_KHR_uniform_buffer_standard_layout
* Search and expose VK_EXT_index_type_uint8
* Search and expose native float16 arithmetics
* Track current driver with VK_KHR_driver_properties
* Query and expose SSBO alignment
* Query more image formats
* Improve logging overall
* Minor style changes
* Minor rephrasing of commentaries