Add worthless (but usable) install.sh

If you're installing a2server out of the source directory (eventually to
become basically the way you do it), this script is going to become the
way you do that.  For now it just runs setup/index.txt.  As we go
through things, we'll move them out of the existing scripts and into a
more modern/modular layout.

install.sh

@@ -0,0 +1,17 @@
+#! /bin/bash
+# vim: set tabstop=4 shiftwidth=4 noexpandtab filetype=sh:
+
+# install.sh - a2server main installation script
+#
+# To the extent possible under law, T. Joseph Carter and Ivan Drucker have
+# waived all copyright and related or neighboring rights to the a2server
+# scripts themselves.  Software used or installed by these scripts is subject
+# to other licenses.  This work is published from the United States.
+
+a2serverVersion="1.9.0"
+a2sScriptURL="https://raw.githubusercontent.com/RasppleII/a2server/master"
+
+# Run the legacy setup script for anything not yet ported
+if [ -e setup/index.txt ]; then
+	source setup/index.txt
+fi