Replace robin_hood map and set with STD alternative and add safeVal() function for map/vector access with fallback

src/btop_shared.cpp

@@ -29,7 +29,7 @@ using namespace Tools;
 namespace Gpu {
 	vector<string> gpu_names;
 	vector<int> gpu_b_height_offsets;
-	unordered_flat_map<string, deque<long long>> shared_gpu_percent = {
+	std::unordered_map<string, deque<long long>> shared_gpu_percent = {
 		{"gpu-average", {}},
 		{"gpu-vram-total", {}},
 		{"gpu-pwr-total", {}},