Remove TactilityC and Firmware subprojects (#638)

- Removed TactilityC, moved its symbols to existing modules and several new ones (pthread-module, c-symbols-module, cpp-symbols-module, posix-symbols-module, freertos-module).
- Removed Firmware subproject and moved main() into Tactility subproject.
- Strengthened application archive, path, version, stack-size, and device validation.
- Moved symbol resolution for elf_loader to app-esp32-module.
- Improved `struct Module` declarations and made module and symbol definitions in modules more consistent.
- Removed old http download code from Tactility subproject.
- Rename app-module's source files for consistency.
- Add missing pthread symbols.
- Kernel module symbols are now resolvable on all platforms.

Modules/app-module/source/internal_loader.cpp

@@ -0,0 +1,48 @@
+// SPDX-License-Identifier: Apache-2.0
+#include <app/loader.h>
+#include <app/manifest.h>
+
+#include <service/instance.h>
+#include <service/manager.h>
+
+namespace {
+
+error_t api_load(AppLocation location, AppRuntime* out_runtime) {
+    if (location.type != APP_LOCATION_MEMORY) {
+        return ERROR_NOT_SUPPORTED;
+    }
+
+    *out_runtime = location.location;
+    return ERROR_NONE;
+}
+
+int32_t api_run(AppRuntime runtime, uint32_t /*app_instance_id*/, int argc, char* argv[]) {
+    auto entry = reinterpret_cast<AppMainFn>(runtime);
+    return entry(argc, argv);
+}
+
+void api_unload(AppRuntime /*unused*/) {
+}
+
+AppLoaderApi memory_loader_api = {
+    .load = api_load,
+    .run = api_run,
+    .unload = api_unload,
+};
+
+void* create_service(const ServiceManifest*) {
+    return &memory_loader_api;
+}
+
+void destroy_service(const ServiceManifest*, void*) {
+}
+
+} // namespace
+
+ServiceManifest app_internal_loader_service_manifest = {
+    .id = APP_LOADER_MEMORY_SERVICE_ID,
+    .create_service = create_service,
+    .destroy_service = destroy_service,
+    .on_start = nullptr,
+    .on_stop = nullptr,
+};