install terminus into /usr/bin on Debian (fixes #433)

build/linux/after-install.tpl

@@ -0,0 +1,4 @@
+#!/bin/bash
+
+# Link to the binary
+ln -sf '/opt/${productFilename}/${executable}' '/usr/bin/${executable}'

package.json

@@ -120,7 +120,8 @@
         "libxtst6",
         "libnss3",
         "tmux"
-      ]
+      ],
+      "afterInstall": "build/linux/after-install.tpl"
     },
     "rpm": {
       "depends": [