Implement specific *all functions

Specific `_*all` and `_*all_with` functions were implemented to make
the API more concise and clean, and to replace the use of
`RELAY_CHN_ID_ALL`, which caused confusion within the API.

Refs #1085

test_apps/main/test_common.c

@@ -39,7 +39,7 @@ const uint8_t gpio_count = sizeof(gpio_map) / sizeof(gpio_map[0]);
 void reset_channels_to_idle_state()
 {
 #if CONFIG_RELAY_CHN_COUNT > 1
-    relay_chn_stop(RELAY_CHN_ID_ALL);
+    relay_chn_stop_all();
     vTaskDelay(pdMS_TO_TICKS(opposite_inertia_ms + test_delay_margin_ms));
     for (int i = 0; i < CONFIG_RELAY_CHN_COUNT; i++) {
         TEST_ASSERT_EQUAL(RELAY_CHN_STATE_IDLE, relay_chn_get_state(i));