M*LIB: non-inlined strings, FuriString primitive (#1795)

* Quicksave 1
* Header stage complete
* Source stage complete
* Lint & merge fixes
* Includes
* Documentation step 1
* FBT: output free size considering BT STACK
* Documentation step 2
* py lint
* Fix music player plugin
* unit test stage 1: string allocator, mem, getters, setters, appends, compare, search.
* unit test: string equality
* unit test: string replace
* unit test: string start_with, end_with
* unit test: string trim
* unit test: utf-8
* Rename
* Revert fw_size changes
* Simplify CLI backspace handling
* Simplify CLI character insert
* Merge fixes
* Furi: correct filenaming and spelling
* Bt: remove furi string include

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

applications/services/gui/modules/text_input.h

@@ -7,7 +7,6 @@
 
 #include <gui/view.h>
 #include "validators.h"
-#include <m-string.h>
 
 #ifdef __cplusplus
 extern "C" {
@@ -16,7 +15,7 @@ extern "C" {
 /** Text input anonymous structure */
 typedef struct TextInput TextInput;
 typedef void (*TextInputCallback)(void* context);
-typedef bool (*TextInputValidatorCallback)(const char* text, string_t error, void* context);
+typedef bool (*TextInputValidatorCallback)(const char* text, FuriString* error, void* context);
 
 /** Allocate and initialize text input 
  *