systemctl-link: add page (#19596)

Co-authored-by: Lena Pastwa <lena@lnps.me>
Co-authored-by: Managor <42655600+Managor@users.noreply.github.com>
Co-authored-by: DustMerlin <39292795+DustMerlin@users.noreply.github.com>

pages/linux/systemctl-link.md

@@ -0,0 +1,13 @@
+# systemctl link
+
+> Link a unit file located outside the unit file search path into the search path.
+> See also: `systemctl disable`.
+> More information: <https://www.freedesktop.org/software/systemd/man/systemctl.html#link%20PATH%E2%80%A6>.
+
+- Link a unit file to make it available for systemd commands:
+
+`systemctl link {{path/to/service}}`
+
+- Link multiple unit files at once:
+
+`systemctl link {{path/to/service1 path/to/service2 ...}}`