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/object/gateway/gw_device.c

@@ -89,7 +89,7 @@ uint16_t iCurrent_Device_Idx = 0;
  *         there isn't enough room to add this Device.
  */
 uint16_t Add_Routed_Device(uint32_t Object_Instance,
-    BACNET_CHARACTER_STRING *sObject_Name,
+    const BACNET_CHARACTER_STRING *sObject_Name,
     const char *sDescription)
 {
     int i = Num_Managed_Devices;
@@ -192,7 +192,7 @@ void routed_get_my_address(BACNET_ADDRESS *my_address)
  *         meaning MAC broadcast, so it's an automatic match).
  *         Else False if no match or invalid idx is given.
  */
-bool Routed_Device_Address_Lookup(int idx, uint8_t dlen, uint8_t *dadr)
+bool Routed_Device_Address_Lookup(int idx, uint8_t dlen, const uint8_t *dadr)
 {
     bool result = false;
     DEVICE_OBJECT_DATA *pDev;
@@ -245,7 +245,8 @@ bool Routed_Device_Address_Lookup(int idx, uint8_t dlen, uint8_t *dadr)
  * match). Else False if no match or invalid idx is given; the cursor will be
  * returned as -1 in these cases.
  */
-bool Routed_Device_GetNext(BACNET_ADDRESS *dest, int *DNET_list, int *cursor)
+bool Routed_Device_GetNext(
+    const BACNET_ADDRESS *dest, const int *DNET_list, int *cursor)
 {
     int dnet = DNET_list[0]; /* Get the DNET of our virtual network */
     int idx = *cursor;
@@ -315,7 +316,7 @@ bool Routed_Device_GetNext(BACNET_ADDRESS *dest, int *DNET_list, int *cursor)
  *          Device (the gateway), or is BACNET_BROADCAST_NETWORK,
  * which is an automatic match. Else False if not a reachable network.
  */
-bool Routed_Device_Is_Valid_Network(uint16_t dest_net, int *DNET_list)
+bool Routed_Device_Is_Valid_Network(uint16_t dest_net, const int *DNET_list)
 {
     int dnet = DNET_list[0]; /* Get the DNET of our virtual network */
     bool bSuccess = false;