[FL-2675] /int space reservation (#1448)

* storage: added global #defines for /int, /ext & /any
* storage: introduced PATH_EXT, PATH_INT& PATH_ANY macros
* core apps: moved hardcoded config files names to separate headers; prefixed them with "."; updater: added file name migration to new naming convention on backup extraction
* storage: fixed storage_merge_recursive handling of complex directory structures; storage_move_to_sd: changed data migration logic to all non-dot files & all folders
* core: added macro aliases for core record names
* Bumped protobuf commit pointer
* storage: reserved 5 pages in /int; denying write&creation of non-dot files when running out of free space

Co-authored-by: あく <alleteam@gmail.com>

lib/toolbox/dir_walk.c

@@ -55,7 +55,7 @@ static bool dir_walk_filter(DirWalk* dir_walk, const char* name, FileInfo* filei
 
 static DirWalkResult dir_walk_iter(DirWalk* dir_walk, string_t return_path, FileInfo* fileinfo) {
     DirWalkResult result = DirWalkError;
-    char* name = malloc(256);
+    char* name = malloc(256); // FIXME: remove magic number
     FileInfo info;
     bool end = false;