astroterm: add page (#17510)

Co-authored-by: Managor <42655600+Managor@users.noreply.github.com>

pages/common/astroterm.md

@@ -0,0 +1,24 @@
+# astroterm
+
+> A terminal-based star map.
+> More information: <https://github.com/da-luce/astroterm#usage>.
+
+- Display real-time positions of stars and planets based on your current location:
+
+`astroterm`
+
+- Display constellations, use colour, and render the simulation at the given frame rate:
+
+`astroterm {{[-C|--constellations]}} {{[-c|--color]}} {{[-f|--fps]}} {{60}}`
+
+- Use unicode characters instead of the basic ASCII characters, and only render stars brighter than the given magnitude:
+
+`astroterm {{[-u|--unicode]}} {{[-t|--threshold]}} {{2.0}}`
+
+- Use a given latitude, longitude and datetime:
+
+`astroterm {{[-a|--latitude]}} {{90.0}} {{[-o|--longitude]}} {{-180.0}} {{[-d|--datetime]}} {{2025-08-04T12:00:00}}`
+
+- Use the longitude and latitude of a given city, and set the speed of the simulation to a given factor:
+
+`astroterm {{[-i|--city]}} {{Singapore}} {{[-s|--speed]}} {{1000.0}}`