Make most of functions const correct (#714)

* Make most of the functions const correct

Used clang-tidy and sonarlint to help find places where const could
pretty easily applied. Also lot of hand work.

This commit does not yet touch handlers and typedefs of those.

* Fix Arduino uno handler_who_is() has extra parenthesis

For some reason there is extra parenthesis. Remove it this is more
likely buildable.

* Bugfix/bacapp: Fix uninitilized array_index

We have changed bacapp_snprintf_value() to be const correct. After that
we got

```
/home/runner/work/bacnet-stack/bacnet-stack/src/bacnet/bacapp.c:3183:27: warning: 4th function call argument is an uninitialized value [core.CallAndMessage]
                ret_val = bacapp_snprintf_weeklyschedule(
                          ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
1 warning generated.
```

So analyzer could now spot that we do not actually initilize array_index
at all. Fix this by setting array_index to zero. Note that I actually do
not know if zeroing is right thing to do here. I choose zero as if this
has worked before it is most likely that it will work with zero value.

* cmake: Add and ignore Wwrite-strings compiler option

Wwrite-strings helps find places where const correctness is broken.

Example it will warn about these

```C

void func1(char* str);

func("test") /* "test" is const so we should not pass it to func1().

char* func2()
{
  return "test"; /* func2() should return const char*.
}
```

We still need to ignore it as not all are fixed but let's add it already
so we remember that it should be opened at some point.

---------

Co-authored-by: Kari Argillander <kari.argillander@fidelix.com>

src/bacnet/basic/client/bac-data.c

@@ -109,8 +109,8 @@ static void bacnet_data_object_init(void)
 }
 
 static void bacnet_data_object_store(int index,
-    BACNET_READ_PROPERTY_DATA *rp_data,
-    BACNET_APPLICATION_DATA_VALUE *value)
+    const BACNET_READ_PROPERTY_DATA *rp_data,
+    const BACNET_APPLICATION_DATA_VALUE *value)
 {
     BACNET_DATA_OBJECT *object = NULL;
 
@@ -189,7 +189,7 @@ void bacnet_data_value_save(uint32_t device_instance,
  * @brief Handles the BACnet Data Analog Value processing
  * @param object - BACnet object structure data pointer
  */
-static void bacnet_data_object_process(BACNET_DATA_OBJECT *object)
+static void bacnet_data_object_process(const BACNET_DATA_OBJECT *object)
 {
     if (object && (object->Device_ID < BACNET_MAX_INSTANCE) &&
         (object->Object_ID < BACNET_MAX_INSTANCE)) {

src/bacnet/basic/client/bac-discover.c

@@ -555,8 +555,8 @@ bool bacnet_discover_object_property_identifier(uint32_t device_id,
  * @param device_data [in] Pointer to the device data structure
  */
 static void bacnet_device_object_property_add(uint32_t device_id,
-    BACNET_READ_PROPERTY_DATA *rp_data,
-    BACNET_APPLICATION_DATA_VALUE *value,
+    const BACNET_READ_PROPERTY_DATA *rp_data,
+    const BACNET_APPLICATION_DATA_VALUE *value,
     BACNET_DEVICE_DATA *device_data)
 {
     BACNET_OBJECT_DATA *object_data;

src/bacnet/basic/client/bac-rw.c

@@ -351,7 +351,7 @@ static uint8_t Send_RPM_All_Request(uint32_t device_id,
  * @param service_request [in] The contents of the service request.
  * @return true if the process is finished
  */
-static bool bacnet_read_write_process(TARGET_DATA *target)
+static bool bacnet_read_write_process(const TARGET_DATA *target)
 {
     bool found = false;
     unsigned max_apdu = 0;