gallery-dl: add page (#10160)

Co-authored-by: Lena <126529524+acuteenvy@users.noreply.github.com>
Co-authored-by: K.B.Dharun Krishna <kbdharunkrishna@gmail.com>

pages/common/gallery-dl.md

@@ -0,0 +1,16 @@
+# gallery-dl
+
+> Download image galleries and collections from several image hosting sites.
+> More information: <https://github.com/mikf/gallery-dl>.
+
+- Download images from the specified URL:
+
+`gallery-dl "{{url}}"`
+
+- Get the direct URL of an image from a site supporting authentication with username and password:
+
+`gallery-dl --get-urls --username {{username}} --password {{password}} "{{url}}"`
+
+- Filter manga chapters by chapter number and language:
+
+`gallery-dl --chapter-filter "{{10 <= chapter < 20}}" --option "lang={{language_code}}" "{{url}}`