lib: move utilities into own folder

Move various utilities out of lib into own folder for better assignement
and management in the maintainer file. lib/os has become another dumping
ground for everything and it the Kconfig and contents in that folder
became difficult to manage, configure and test.

Signed-off-by: Anas Nashif <anas.nashif@intel.com>

tests/unit/base64/main.c

@@ -27,7 +27,7 @@
 #include <zephyr/sys/base64.h>
 #include <zephyr/ztest.h>
 
-#include "../../../lib/os/base64.c"
+#include "../../../lib/utils/base64.c"
 
 static const unsigned char base64_test_dec[64] = {
 	0x24, 0x48, 0x6E, 0x56, 0x87, 0x62, 0x5A, 0xBD,

tests/unit/rbtree/main.c

@@ -6,7 +6,7 @@
 #include <zephyr/ztest.h>
 #include <zephyr/sys/rb.h>
 
-#include "../../../lib/os/rb.c"
+#include "../../../lib/utils/rb.c"
 
 #define _CHECK(n) \
 	zassert_true(!!(n), "Tree check failed: [ " #n " ] @%d", __LINE__)

tests/unit/timeutil/main.c

@@ -6,7 +6,7 @@
 
 #include <zephyr/ztest.h>
 #include "timeutil_test.h"
-#include "../../../lib/os/timeutil.c"
+#include "../../../lib/utils/timeutil.c"
 
 void timeutil_check(const struct timeutil_test_data *tp,
 		    size_t count)

tests/unit/util/CMakeLists.txt

@@ -4,4 +4,4 @@ cmake_minimum_required(VERSION 3.20.0)
 
 project(util)
 find_package(Zephyr COMPONENTS unittest REQUIRED HINTS $ENV{ZEPHYR_BASE})
-target_sources(testbinary PRIVATE main.c maincxx.cxx ${ZEPHYR_BASE}/lib/os/dec.c)
+target_sources(testbinary PRIVATE main.c maincxx.cxx ${ZEPHYR_BASE}/lib/utils/dec.c)

tests/unit/winstream/main.c

@@ -8,7 +8,7 @@
 /* This, uh, seems to be the standard way to unit test library code.
  * Or so I gather from tests/unit/rbtree ...
  */
-#include "../../../lib/os/winstream.c"
+#include "../../../lib/utils/winstream.c"
 
 #define BUFLEN 64