Unicorn has been removed, yet CI still enables building with Unicorn.
This just cleans up a few leftovers by removing the variable from the
CMake parameters in CI.
* Remove git submodules that will be loaded through conan
* Move custom Find modules to their own folder
* Use conan for downloading missing external dependencies
* CI: Change the yuzu source folder user to the user that the containers run on
* Attempt to remove dirty mingw build hack
* Install conan on the msvc build
* Only set release build type when using not using multi config generator
* Re-add qt bundled to workaround an issue with conan qt not downloading prebuilt binaries
* Add workaround for submodules that use legacy CMAKE variables
* Re-add USE_BUNDLED_QT on the msvc build bot
This is possible now with the updated Docker images and their updated packages.
Before, there were build errors due to old QT5 packages on Ubuntu, but now since
they have updated packages it is feasible to build with Vulkan enabled once more.