Replace externals with Conan (#3735)

* 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

externals/find-modules/Findfmt.cmake

@@ -0,0 +1,43 @@
+
+find_package(PkgConfig QUIET)
+pkg_check_modules(PC_fmt QUIET fmt)
+
+find_path(fmt_INCLUDE_DIR
+  NAMES format.h
+  PATHS ${PC_fmt_INCLUDE_DIRS} ${CONAN_INCLUDE_DIRS_fmt}
+  PATH_SUFFIXES fmt
+)
+
+find_library(fmt_LIBRARY
+  NAMES fmt
+  PATHS ${PC_fmt_LIBRARY_DIRS} ${CONAN_LIB_DIRS_fmt}
+)
+
+include(FindPackageHandleStandardArgs)
+find_package_handle_standard_args(fmt
+  FOUND_VAR fmt_FOUND
+  REQUIRED_VARS
+    fmt_LIBRARY
+    fmt_INCLUDE_DIR
+  VERSION_VAR fmt_VERSION
+)
+
+if(fmt_FOUND)
+  set(fmt_LIBRARIES ${fmt_LIBRARY})
+  set(fmt_INCLUDE_DIRS ${fmt_INCLUDE_DIR})
+  set(fmt_DEFINITIONS ${PC_fmt_CFLAGS_OTHER})
+endif()
+
+if(fmt_FOUND AND NOT TARGET fmt::fmt)
+  add_library(fmt::fmt UNKNOWN IMPORTED)
+  set_target_properties(fmt::fmt PROPERTIES
+    IMPORTED_LOCATION "${fmt_LIBRARY}"
+    INTERFACE_COMPILE_OPTIONS "${PC_fmt_CFLAGS_OTHER}"
+    INTERFACE_INCLUDE_DIRECTORIES "${fmt_INCLUDE_DIR}"
+  )
+endif()
+
+mark_as_advanced(
+    fmt_INCLUDE_DIR
+    fmt_LIBRARY
+)