Various improvements: Toolbox, Updater and Unit Tests. (#2250)

* Toolbox: add seek to character stream method. UpdateUtils: reverse manifest iterator. UnitTests: more unit tests.
* Target: bump API version. Updater: delete empty folders from manifest before resource deployment.
* UnitTests: use manifest from unit_tests folder instead of global one
* Make PVS happy
* sector cache: allocate always
* Better PVS config for manifest.c
* PVS: Move exception outside of condition
* PVS: remove confusing condition

Co-authored-by: SG <who.just.the.doctor@gmail.com>

lib/update_util/resources/manifest.h

@@ -11,6 +11,8 @@ extern "C" {
 
 typedef enum {
     ResourceManifestEntryTypeUnknown = 0,
+    ResourceManifestEntryTypeVersion,
+    ResourceManifestEntryTypeTimestamp,
     ResourceManifestEntryTypeDirectory,
     ResourceManifestEntryTypeFile,
 } ResourceManifestEntryType;
@@ -52,6 +54,18 @@ bool resource_manifest_reader_open(ResourceManifestReader* resource_manifest, co
  */
 ResourceManifestEntry* resource_manifest_reader_next(ResourceManifestReader* resource_manifest);
 
+/** Read previous file/dir entry from manifest
+ *
+ * You must be at the end of the manifest to use this function.
+ * Intended to be used after reaching end with resource_manifest_reader_next
+ *
+ * @param      resource_manifest  Pointer to the ResourceManifestReader instance
+ *
+ * @return     entry or NULL if end of file
+ */
+ResourceManifestEntry*
+    resource_manifest_reader_previous(ResourceManifestReader* resource_manifest);
+
 #ifdef __cplusplus
 } // extern "C"
 #endif