Lock TextureManager/BufferManager during submission

Multiple threads concurrently accessing the `TextureManager`/`BufferManager` (Referred to as "resource managers") has a potential deadlock with a resource being locked while acquiring the resource manager lock while the thread owning it tries to acquire a lock on the resource resulting in a deadlock.

This has been fixed with locking of resource manager now being externally handled which ensures it can be locked prior to locking any resources, `CommandExecutor` provides accessors for retrieving the resource manager which automatically handles locking aside doing so on attachment of resources.

app/src/main/cpp/skyline/gpu/texture_manager.cpp

@@ -6,6 +6,18 @@
 namespace skyline::gpu {
     TextureManager::TextureManager(GPU &gpu) : gpu(gpu) {}
 
+    void TextureManager::lock() {
+        mutex.lock();
+    }
+
+    void TextureManager::unlock() {
+        mutex.unlock();
+    }
+
+    bool TextureManager::try_lock() {
+        return mutex.try_lock();
+    }
+
     std::shared_ptr<TextureView> TextureManager::FindOrCreate(const GuestTexture &guestTexture, ContextTag tag) {
         auto guestMapping{guestTexture.mappings.front()};
 
@@ -23,7 +35,6 @@ namespace skyline::gpu {
          * 5) Create a new texture and insert it in the map then return it
          */
 
-        std::scoped_lock lock(mutex);
         std::shared_ptr<Texture> match{};
         auto mappingEnd{std::upper_bound(textures.begin(), textures.end(), guestMapping)}, hostMapping{mappingEnd};
         while (hostMapping != textures.begin() && (--hostMapping)->end() > guestMapping.begin()) {