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>

ports/stm32f4xx/device.c

@@ -345,7 +345,7 @@ bool Device_Object_Name(
     return status;
 }
 
-bool Device_Set_Object_Name(BACNET_CHARACTER_STRING *object_name)
+bool Device_Set_Object_Name(const BACNET_CHARACTER_STRING *object_name)
 {
     bool status = false; /*return value */
 
@@ -478,7 +478,7 @@ void Device_UUID_Init(void)
  * @param new_uuid [in] The new UUID to set
  * @param length [in] The length of the new UUID
  */
-void Device_UUID_Set(uint8_t *new_uuid, size_t length)
+void Device_UUID_Set(const uint8_t *new_uuid, size_t length)
 {
     if (new_uuid && (length == sizeof(Device_UUID))) {
         memcpy(Device_UUID, new_uuid, sizeof(Device_UUID));
@@ -603,7 +603,7 @@ int Device_Object_List_Element_Encode(
  * Object.
  * @return True on success or else False if not found.
  */
-bool Device_Valid_Object_Name(BACNET_CHARACTER_STRING *object_name1,
+bool Device_Valid_Object_Name(const BACNET_CHARACTER_STRING *object_name1,
     BACNET_OBJECT_TYPE *object_type,
     uint32_t *object_instance)
 {
@@ -842,7 +842,8 @@ int Device_Read_Property_Local(BACNET_READ_PROPERTY_DATA *rpdata)
  * @return The length of the APDU on success, else BACNET_STATUS_ERROR
  */
 static int Read_Property_Common(
-    struct my_object_functions *pObject, BACNET_READ_PROPERTY_DATA *rpdata)
+    const struct my_object_functions *pObject,
+    BACNET_READ_PROPERTY_DATA *rpdata)
 {
     int apdu_len = BACNET_STATUS_ERROR;
     BACNET_CHARACTER_STRING char_string;

ports/stm32f4xx/netport.c

@@ -299,7 +299,7 @@ bool Network_Port_MAC_Address(
  * @return  true if object-name was set
  */
 bool Network_Port_MAC_Address_Set(
-    uint32_t object_instance, uint8_t *mac_src, uint8_t mac_len)
+    uint32_t object_instance, const uint8_t *mac_src, uint8_t mac_len)
 {
     if (mac_len == 1) {
         Object_List[0].MAC_Address[0] = mac_src[0];

ports/stm32f4xx/rs485.c

@@ -209,7 +209,7 @@ bool rs485_byte_available(uint8_t *data_register)
  * @param nbytes - number of bytes to transmit
  * @return true if added to queue
  */
-void rs485_bytes_send(uint8_t *buffer, uint16_t nbytes)
+void rs485_bytes_send(const uint8_t *buffer, uint16_t nbytes)
 {
     if (buffer && (nbytes > 0)) {
         if (FIFO_Add(&Transmit_Queue, buffer, nbytes)) {

ports/stm32f4xx/rs485.h

@@ -20,7 +20,7 @@ bool rs485_rts_enabled(void);
 bool rs485_byte_available(uint8_t *data_register);
 bool rs485_receive_error(void);
 
-void rs485_bytes_send(uint8_t *buffer, uint16_t nbytes);
+void rs485_bytes_send(const uint8_t *buffer, uint16_t nbytes);
 
 uint32_t rs485_baud_rate(void);
 bool rs485_baud_rate_set(uint32_t baud);