speedtest: add page (#5282)

pages/linux/speedtest.md

@@ -0,0 +1,20 @@
+# speedtest
+
+> Test internet bandwidth using https://www.speedtest.net.
+> More information: <https://www.speedtest.net/apps/cli>.
+
+- Run a basic speedtest:
+
+`speedtest`
+
+- Display values in bytes instead of bits:
+
+`speedtest --bytes`
+
+- Use HTTPS instead of HTTP:
+
+`speedtest --secure`
+
+- List servers sorted by distance:
+
+`speedtest --list`