Undo some TODO (#3024)

* TODO FL-3497: impossible to fix with current memory allocator

* TODO FL-3497: removed, requires radically different settings approach

* TODO FL-3514: removed, yes we should

* TODO FL-3498: implemented, guarding view port access with mutex.

* TODO FL-3515: removed, questionable but ok

* TODO FL-3510: removed, comment added

* TODO FL-3500: refactored, store pin numbers in GpioPinRecord, fix gpio app crash caused by incorrect gpio_pins traversal.

* Format Sources

* TODO FL-3505: removed, mutex alone is not going to fix issue with WPAN architecture

* TODO FL-3506: removed, change ownership by copy is good

* TODO FL-3519: documentation and link to source added

* Lib: remove unneded total sum from comment in bq27220

---------

Co-authored-by: hedger <hedger@users.noreply.github.com>

applications/debug/unit_tests/furi/furi_memmgr_test.c

@@ -26,7 +26,6 @@ void test_furi_memmgr() {
         mu_assert_int_eq(66, ((uint8_t*)ptr)[i]);
     }
 
-    // TODO FL-3492: fix realloc to copy only old size, and write testcase that leftover of reallocated memory is zero-initialized
     free(ptr);
 
     // allocate and zero-initialize array (calloc)