Return EXIT_FAILURE on post-init fatal errors

It seems odd to return `EXIT_SUCCESS` when the node aborted
execution due a fatal internal error or any post-init problem
that triggers an unrequested shutdown.

e.g. blocks or coins db I/O errors, disconnect block failure,
failure during thread import (external blocks loading process
error), among others.

Co-authored-by: Ryan Ofsky <ryan@ofsky.org>

src/init.h

@@ -38,7 +38,7 @@ void InitParameterInteraction(ArgsManager& args);
  *  @note This can be done before daemonization. Do not call Shutdown() if this function fails.
  *  @pre Parameters should be parsed and config file should be read.
  */
-bool AppInitBasicSetup(const ArgsManager& args);
+bool AppInitBasicSetup(const ArgsManager& args, std::atomic<int>& exit_status);
 /**
  * Initialization: parameter interaction.
  * @note This can be done before daemonization. Do not call Shutdown() if this function fails.