ALICE: new external resources record

* Creates `alice-external-resources.xml`.  (closes #384) (PR #464)
docs: new file `alice-external-resources.xml`

* Updates installation instructions after addition of new file
  `alice-external-resources.xml`.  (see PR #464)
LHCb: new file `lhcb-tools.xml`

* Creates new file `lhcb-tools.xml`.  (addresses #320) (PR #457)
collections: fix "error" when coll. name is wrong

* redirects to “404” page when collection name given is doesn’t exist
* ( closes #452 )
UI: fixes bcg-color in "404" pages
CMS: external VM link -> opendata-link (recid-250)

* (closes #472)
UI: fixes dropdown menu overlapping

* ( closes #473)
UI: adds a homepage alternative as '/home8'

* ( addresses #467 )
UI: fixes/reverts logo to previous state