Feature proposal : darkmode (#85)

* Create dark-style.css

* Add call to get_color_scheme

* Add call to get_color_scheme

* Create get_color_scheme function

* Add selection box in config.php

* Accept both lower and uppercase COLOR_SCHEME

* Add COLOR_SCHEME

* Add COLOR_SCHEME

* Change birdnet.conf after color scheme selection

* Move css to static to enable it

* Adapt css location to static

* Improve opacity value

* Fix logo background issues on smaller screens

* Avoid overlap of logos

* Ensure clean look (same margin as before but different location)

* Default background as transparent to avoid white on white

* Avoid black on dark ; improve readability

* Last element of green is homogenized to grayscale

* Enable site reload after color_scheme change

scripts/update_birdnet_snippets.sh

@@ -90,6 +90,10 @@ if ! grep -E '^INFO_SITE=' /etc/birdnet/birdnet.conf &>/dev/null;then
   echo "INFO_SITE=\"ALLABOUTBIRDS\"" >> /etc/birdnet/birdnet.conf
 fi
 
+if ! grep -E '^COLOR_SCHEME=' /etc/birdnet/birdnet.conf &>/dev/null;then
+  echo "COLOR_SCHEME=\"light\"" >> /etc/birdnet/birdnet.conf
+fi
+
 [ -d $RECS_DIR/StreamData ] || sudo_with_user mkdir -p $RECS_DIR/StreamData
 [ -L ${EXTRACTED}/spectrogram.png ] || sudo_with_user ln -sf ${RECS_DIR}/StreamData/spectrogram.png ${EXTRACTED}/spectrogram.png