waybar: Add keepawake module

Shows if the pc will not automatically turn off screen or suspend.
Figures this out by checking for `swayidle` process, so that is
required. Turns on suspend again on click, and uses voidlinux `sv` user
service for it, so those have to be set up.

desktop/.config/waybar/config

@@ -1,8 +1,21 @@
 {
     "layer": "top",
     "modules-left": ["river/tags", "custom/events", "custom/vidl", "river/window"],
-    "modules-center": ["clock", "custom/media"],
+    "modules-center": ["clock", "custom/media", "custom/keepawake"],
     "modules-right": ["river/mode", "custom/wireguard", "custom/archupdates", "pulseaudio", "backlight", "network", "cpu", "memory", "temperature", "tray", "battery"],
+    "custom/keepawake": {
+        "format": "{icon}",
+        "format-alt": "{} {icon}",
+        "format-alt-click": "click-right",
+        "format-icons": {
+            "idle-disabled": "󰅶 ",
+            "idle-enabled": ""
+        },
+        "exec": "~/.config/waybar/modules/keepawake",
+        "on-click": "SVDIR=~/.local/state/service sv start swayidle",
+        "return-type": "json",
+        "interval": 5
+    },
     "custom/archupdates": {
         "format": "{icon}",
         "format-alt": "{} {icon}",