imagemagick: update pages (#12874)

* compare, convert, identify, import, mogrify, montage:
   move pages to subcommands of `magick`, create alias pages

* convert: add deprecation notice

---------

Co-authored-by: K.B.Dharun Krishna <kbdharunkrishna@gmail.com>

pages/common/magick-import.md

@@ -0,0 +1,17 @@
+# magick import
+
+> Capture some or all of an X server screen and save the image to a file.
+> See also: `magick`.
+> More information: <https://imagemagick.org/script/import.php>.
+
+- Capture the entire X server screen into a PostScript file:
+
+`magick import -window root {{path/to/output.ps}}`
+
+- Capture contents of a remote X server screen into a PNG image:
+
+`magick import -window root -display {{remote_host}}:{{screen}}.{{display}} {{path/to/output.png}}`
+
+- Capture a specific window given its ID as displayed by `xwininfo` into a JPEG image:
+
+`magick import -window {{window_id}} {{path/to/output.jpg}}`