Removes the NVENC entry on systems without an NVIDIA GPU by checking if the library for it can be loaded. If it can't be loaded, it's likely that the user does not have a system with NVENC capabilities - and guaranteed that they can't use the encoder as FFmpeg relies on these libraries.
Changes applied:
* Moved utility files to /util/.
* Removed unused #includes.
* Removed unused ::ffmpeg::tools function.
* Removed unused variables.
* Fixed missing parentheses in the version macro.
* Fixed missing override on virtual function overrides and removed unnecessary virtual keyword from them.
* Disabled additional warning for ATL headers on MSVC only.
* Replaced direct printf parameters with their macro equivalent.
* Replaced C-style casts with C++-style casts.
* Applied clang-format again after an earlier change to the CMake file broke the integration for it.
The levels 5.2 and above were added in a newer FFmpeg version than OBS Studio is shipping with. Ideally we'd take these options directly from FFmpeg, but that is for a future commit.
Fixes the issue where "high444p" shows as "high", and "high" shows as "main", caused by the internal option mapping never being correct across version changes. Instead of keeping our own copy of things that has to be adjusted for each FFmpeg version, it's easier to just use the FFmpeg values and names.
* "Quality" Minimum/Maximum is actually QP Minimum/Maximum
* Bitrate Limits is now just Limits
* Buffer Size and Quality Target have been moved into "Limits".
