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>

test/bacnet/datalink/bvlc/src/main.c

@@ -22,14 +22,15 @@
  * @brief Test
  */
 static void test_BVLC_Address(
-    BACNET_IP_ADDRESS *bip_address_1, BACNET_IP_ADDRESS *bip_address_2)
+    const BACNET_IP_ADDRESS *bip_address_1,
+    const BACNET_IP_ADDRESS *bip_address_2)
 {
     zassert_false(bvlc_address_different(bip_address_1, bip_address_2), NULL);
 }
 
 static void test_BVLC_Broadcast_Distribution_Mask(
-    BACNET_IP_BROADCAST_DISTRIBUTION_MASK *bd_mask_1,
-    BACNET_IP_BROADCAST_DISTRIBUTION_MASK *bd_mask_2)
+    const BACNET_IP_BROADCAST_DISTRIBUTION_MASK *bd_mask_1,
+    const BACNET_IP_BROADCAST_DISTRIBUTION_MASK *bd_mask_2)
 {
     zassert_false(
         bvlc_broadcast_distribution_mask_different(bd_mask_1, bd_mask_2), NULL);
@@ -68,7 +69,7 @@ static void test_BVLC_Foreign_Device_Table_Entry(
 }
 
 static int test_BVLC_Header(
-    uint8_t *pdu,
+    const uint8_t *pdu,
     uint16_t pdu_len,
     uint8_t *message_type,
     uint16_t *message_length)
@@ -175,8 +176,8 @@ static void test_BVLC_Original_Unicast_NPDU(void)
     test_BVLC_Original_Unicast_NPDU_Message(npdu, npdu_len);
 }
 
-static void
-test_BVLC_Original_Broadcast_NPDU_Message(uint8_t *npdu, uint16_t npdu_len)
+static void test_BVLC_Original_Broadcast_NPDU_Message(
+    const uint8_t *npdu, uint16_t npdu_len)
 {
     uint8_t test_npdu[50] = { 0 };
     uint8_t pdu[60] = { 0 };
@@ -223,7 +224,9 @@ static void test_BVLC_Original_Broadcast_NPDU(void)
 }
 
 static void test_BVLC_Forwarded_NPDU_Message(
-    uint8_t *npdu, uint16_t npdu_len, BACNET_IP_ADDRESS *bip_address)
+    const uint8_t *npdu,
+    uint16_t npdu_len,
+    const BACNET_IP_ADDRESS *bip_address)
 {
     uint8_t test_npdu[50] = { 0 };
     uint8_t pdu[75] = { 0 };
@@ -314,7 +317,7 @@ static void test_BVLC_Register_Foreign_Device(void)
 }
 
 static void test_BVLC_Delete_Foreign_Device_Message(
-    BACNET_IP_FOREIGN_DEVICE_TABLE_ENTRY *fdt_entry)
+    const BACNET_IP_FOREIGN_DEVICE_TABLE_ENTRY *fdt_entry)
 {
     uint8_t pdu[64] = { 0 };
     BACNET_IP_FOREIGN_DEVICE_TABLE_ENTRY test_fdt_entry = { 0 };
@@ -362,7 +365,8 @@ static void test_BVLC_Delete_Foreign_Device(void)
     test_BVLC_Delete_Foreign_Device_Message(&fdt_entry);
 }
 
-static void test_BVLC_Secure_BVLL_Message(uint8_t *sbuf, uint16_t sbuf_len)
+static void test_BVLC_Secure_BVLL_Message(
+    const uint8_t *sbuf, uint16_t sbuf_len)
 {
     uint8_t test_sbuf[50] = { 0 };
     uint8_t pdu[60] = { 0 };
@@ -429,7 +433,7 @@ static void test_BVLC_Read_Broadcast_Distribution_Table_Message(void)
 }
 
 static void test_BVLC_Distribute_Broadcast_To_Network_Message(
-    uint8_t *npdu, uint16_t npdu_len)
+    const uint8_t *npdu, uint16_t npdu_len)
 {
     uint8_t test_npdu[50] = { 0 };
     uint8_t pdu[60] = { 0 };