CMS: update of `cms-tools-ispy.xml`

* Updates `cms-tools-ispy.xml`.  (closes #424) (PR #461)
CMS: update of `cms-tools-ana.xml`

* Updates `cms-tools-ana.xml`.  (closes #424) (PR #462)
CMS: new `cms-tools-dimuon-filter.xml`

* Adds new file `cms-tools-dimuon-filter.xml`.  (closes #412) (PR #459)
docs: new file `cms-tools-dimuon-filter.xml`

* Updates installation instructions after addition of new file
  `cms-tools-dimuon-filter.xml`.  (see PR #459)

Signed-off-by: Tibor Simko <tibor.simko@cern.ch>
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)