Implemented LaunchId and FileSelection, updated Notes (#281)

- Implemented `LaunchId` to keep track of the apps that are started
- Implemented `FileSelection` app to select existing and/or new files.
- Moved some re-usable file functionality to `tt::file::`
- Renamed `Files` app to `FileBrowser`
- Updated `Notes` app to use new `FileSelection` functionality, and cleaned it up a bit.
- General code cleanliness improvements

Tactility/Source/app/filebrowser/SupportedFiles.cpp

@@ -0,0 +1,34 @@
+#include <Tactility/StringUtils.h>
+#include <Tactility/TactilityCore.h>
+
+namespace tt::app::filebrowser {
+
+#define TAG "filebrowser_app"
+
+bool isSupportedExecutableFile(const std::string& filename) {
+#ifdef ESP_PLATFORM
+    // Currently only the PNG library is built into Tactility
+    return filename.ends_with(".elf");
+#else
+    return false;
+#endif
+}
+
+bool isSupportedImageFile(const std::string& filename) {
+    // Currently only the PNG library is built into Tactility
+    return string::lowercase(filename).ends_with(".png");
+}
+
+bool isSupportedTextFile(const std::string& filename) {
+    std::string filename_lower = string::lowercase(filename);
+    return filename_lower.ends_with(".txt") ||
+        filename_lower.ends_with(".ini") ||
+        filename_lower.ends_with(".json") ||
+        filename_lower.ends_with(".yaml") ||
+        filename_lower.ends_with(".yml") ||
+        filename_lower.ends_with(".lua") ||
+        filename_lower.ends_with(".js") ||
+        filename_lower.ends_with(".properties");
+}
+
+} // namespace tt::app::filebrowser