search: facets per collection configuration

* Adds initial configuration with fixtures.

* NOTE to get facets shown
  invenio_demosite.base.fixtures.websearchh.FacetCollectionData needs
  to be loaded which means that you either need to recreate DB or
  load them manually.

Signed-off-by: Kamil Neczaj <kamil.neczaj@cern.ch>
installation: cleanup requirements

* Removes all packages except from invenio, Flask-Admin and workflow.

* Updates Flask-Admin to 1.0.9.dev0 version.

Signed-off-by: Harris Tzovanakis <me@drjova.ch>
Reviewed-by: Jiri Kuncar <jiri.kuncar@cern.ch>
travis: addition of required --yes-i-know argument

* Amends usage of `inveniomanage demosite populate --yes-i-know`
  command.  (addresses inveniosoftware/invenio#2294)

Signed-off-by: Jiri Kuncar <jiri.kuncar@cern.ch>
base: Typo fix in receivers.py

* "hadler" -> "handler"

Signed-off-by: Joe MacMahon <joe.macmahon@cern.ch>