Add keyboard shortcuts for Elgato key lights

- create Gnome keyboard shortcuts to manage the Elgato key lights:
  + toggle
  + increase and decrease brightness
- we use Python scripts in ~/.config/gnome-settings/elgato
  based on the "leglight" PIP package
  (Source: https://gitlab.com/obviate.io/pyleglight)

.config/gnome-settings/elgato/README.md

@@ -0,0 +1,5 @@
+# Elgato Key Lights
+
+The Python files in this folder are hooked as keyboard shortcuts in Gnome.
+They allow to toggle the key lights in my office.
+In the long-run, these scripts should be improved a bit.

.config/gnome-settings/elgato/dec_brightness.py

@@ -0,0 +1,12 @@
+#!/usr/bin/env python
+
+import leglight
+
+LEFT_KEYLIGHT_IP = "192.168.20.72"
+RIGHT_KEYLIGHT_IP = "192.168.20.73"
+
+left = leglight.LegLight(LEFT_KEYLIGHT_IP, port=9123)
+right = leglight.LegLight(RIGHT_KEYLIGHT_IP, port=9123)
+
+left.decBrightness(5)
+right.decBrightness(5)

.config/gnome-settings/elgato/inc_brightness.py

@@ -0,0 +1,12 @@
+#!/usr/bin/env python
+
+import leglight
+
+LEFT_KEYLIGHT_IP = "192.168.20.72"
+RIGHT_KEYLIGHT_IP = "192.168.20.73"
+
+left = leglight.LegLight(LEFT_KEYLIGHT_IP, port=9123)
+right = leglight.LegLight(RIGHT_KEYLIGHT_IP, port=9123)
+
+left.incBrightness(5)
+right.incBrightness(5)

.config/gnome-settings/elgato/toggle_keylights.py

@@ -0,0 +1,21 @@
+#!/usr/bin/env python
+
+import leglight
+
+LEFT_KEYLIGHT_IP = "192.168.20.72"
+RIGHT_KEYLIGHT_IP = "192.168.20.73"
+
+left = leglight.LegLight(LEFT_KEYLIGHT_IP, port=9123)
+right = leglight.LegLight(RIGHT_KEYLIGHT_IP, port=9123)
+
+if left.info()["on"] or right.info()["on"]:
+    left.off()
+    right.off()
+
+else:
+    left.on()
+    right.on()
+    left.brightness(30)
+    right.brightness(30)
+    left.color(6000)
+    right.color(6000)

.config/gnome-settings/key-bindings.ini

@@ -50,7 +50,7 @@ toggle-tiled-left=@as []
 toggle-tiled-right=@as []
 
 [org/gnome/settings-daemon/plugins/media-keys]
-custom-keybindings=['/org/gnome/settings-daemon/plugins/media-keys/custom-keybindings/custom0/', '/org/gnome/settings-daemon/plugins/media-keys/custom-keybindings/custom1/', '/org/gnome/settings-daemon/plugins/media-keys/custom-keybindings/custom2/', '/org/gnome/settings-daemon/plugins/media-keys/custom-keybindings/custom3/', '/org/gnome/settings-daemon/plugins/media-keys/custom-keybindings/custom4/', '/org/gnome/settings-daemon/plugins/media-keys/custom-keybindings/custom5/', '/org/gnome/settings-daemon/plugins/media-keys/custom-keybindings/custom6/']
+custom-keybindings=['/org/gnome/settings-daemon/plugins/media-keys/custom-keybindings/custom0/', '/org/gnome/settings-daemon/plugins/media-keys/custom-keybindings/custom1/', '/org/gnome/settings-daemon/plugins/media-keys/custom-keybindings/custom2/', '/org/gnome/settings-daemon/plugins/media-keys/custom-keybindings/custom3/', '/org/gnome/settings-daemon/plugins/media-keys/custom-keybindings/custom4/', '/org/gnome/settings-daemon/plugins/media-keys/custom-keybindings/custom5/', '/org/gnome/settings-daemon/plugins/media-keys/custom-keybindings/custom6/', '/org/gnome/settings-daemon/plugins/media-keys/custom-keybindings/custom7/', '/org/gnome/settings-daemon/plugins/media-keys/custom-keybindings/custom8/', '/org/gnome/settings-daemon/plugins/media-keys/custom-keybindings/custom9/']
 email=['<Super>e']
 help=@as []
 home=['<Super>f']
@@ -106,6 +106,21 @@ binding='<Super>t'
 command='gnome-terminal'
 name='Terminal (2)'
 
+[org/gnome/settings-daemon/plugins/media-keys/custom-keybindings/custom7]
+binding='<Shift><Control>l'
+command='/home/alexander/.pyenv/versions/utils/bin/python /home/alexander/.config/gnome-settings/elgato/toggle_keylights.py'
+name='Toggle Keylights in the Office'
+
+[org/gnome/settings-daemon/plugins/media-keys/custom-keybindings/custom8]
+binding='<Shift><Control>Up'
+command='/home/alexander/.pyenv/versions/utils/bin/python /home/alexander/.config/gnome-settings/elgato/inc_brightness.py'
+name='Increase Brightness of Keylights in the Office'
+
+[org/gnome/settings-daemon/plugins/media-keys/custom-keybindings/custom9]
+binding='<Shift><Control>Down'
+command='/home/alexander/.pyenv/versions/utils/bin/python /home/alexander/.config/gnome-settings/elgato/dec_brightness.py'
+name='Decrease Brightness of Keylights in the Office'
+
 [org/gnome/shell/extensions/pop-shell]
 activate-launcher=['<Super>d']
 pop-workspace-down=['<Primary><Alt>Down']

.config/shell/utils.sh

@@ -210,7 +210,7 @@ _py2_version='2.7.18'
 _py3_site_packages=('black' 'pipenv' 'poetry')
 
 # The pyenv virtualenv "utils" contains some globally available tools (e.g., mackup)
-_py3_utils=('mackup' 'youtube-dl')
+_py3_utils=('leglight' 'mackup' 'youtube-dl')
 
 # Important: this REMOVES the old ~/.pyenv installation
 _install_pyenv() {