[FL-3884] Proper integer parsing (#3839)

* feat: strint_to_uint32 and tests
* fix: permit explicit bases and prefixes
* feat: strint_to_{int32,uint16,int16}
* feat: strint_to_u?int64
* refactor: replace strtol, strtoul, sscanf with strint_to_*
* fix: api symbols
* docs: document parameter `end` of strint_to_uint_32
* style: apply changes requested by hedger
* refactor: fix pvs-studio diagnostic
* style: apply changes requested by CookiePLMonster
* fix: unused var
* fix: pointer type
* refactor: convert atoi to strint_to_*
* fix: strint_to_uint8 doesn't actually exist ._ .
* fix: memory leak
* style: address review comments
* Toolbox: couple small comments in the code and doxygen comment update. SubGhz, Loader: fix strint usage.
* Loader: fix incorrect cast

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

applications/debug/uart_echo/uart_echo.c

@@ -6,6 +6,8 @@
 #include <gui/view_dispatcher.h>
 #include <gui/modules/dialog_ex.h>
 
+#include <lib/toolbox/strint.h>
+
 #include <notification/notification.h>
 #include <notification/notification_messages.h>
 
@@ -320,7 +322,7 @@ int32_t uart_echo_app(void* p) {
     uint32_t baudrate = DEFAULT_BAUD_RATE;
     if(p) {
         const char* baudrate_str = p;
-        if(sscanf(baudrate_str, "%lu", &baudrate) != 1) {
+        if(strint_to_uint32(baudrate_str, NULL, &baudrate, 10) != StrintParseNoError) {
             FURI_LOG_E(TAG, "Invalid baudrate: %s", baudrate_str);
             baudrate = DEFAULT_BAUD_RATE;
         }