Refactor Tephra

[Alairion]

• [x] Remove global context
• [x] Rename renderer
• [x] Make a function for basic VkResult check and throw
• [x] Rename variables (function parameters)
• [ ] Check header and runtime version for function calls
• [ ] Use Sync2 internally
  • [ ] Expose only Sync2 and convert on flight if no ext and Vk < 1.3
  • [ ] Enable ext by default for Vk < 1.3
• [ ] Add missing features from Vk 1.2 and 1.3