fix #1639 only disallow "apps"
fix #1639 only disallow "apps"

For prod & dev (testing), allow /, but disallow sim_types, because
we don't want robots hitting our js.
For alpha & beta, disallow /

mkeilman/sirepo,mrakitin/sirepo,radiasoft/sirepo,mrakitin/sirepo,mrakitin/sirepo,radiasoft/sirepo,mrakitin/sirepo,radiasoft/sirepo,mkeilman/sirepo,mkeilman/sirepo,mkeilman/sirepo,radiasoft/sirepo,radiasoft/sirepo