UI: standardising text for "VM"

* replaces “Working Environments” -> “Virtual Machines”
* ( addresses #425 )
UI: adds option to exclude experiment from a page

* ( addresses #477)
UI: removes ATLAS VM section + page

* (closes #477)
LHCb: introduce VM page

* ( closes #499)
LHCb: introduce getting started page

* (closes #500)
LHCb: update of `lhcb-external-resources.xml`

* Amends FIXME text for LHCb external resources file.
  (closes #486) (PR #496)
fixtures: LHCb collection description update

* Updates tiny descriptions for LHCb collections.
  (closes #497) (PR #496)
LHCb: addition of EOS file indexes

* Adds EOS file indexes files for upload.  Amends MARCXML file and
  installation instructions accordingly.  (closes #495)

Signed-off-by: Tibor Simko <tibor.simko@cern.ch>
ATLAS: addition of EOS file indexes

* Adds EOS file indexes files for upload.  Amends MARCXML file and
  installation instructions accordingly.  (closes #512)

Signed-off-by: Tibor Simko <tibor.simko@cern.ch>
records: fix iframe previewer and buttons

* Fixes iframe previewer for ispy-online. (closes #340)

Signed-off-by: Jiri Kuncar <jiri.kuncar@cern.ch>

Conflicts:
	invenio_opendata/base/templates/records/ALICE-Derived-Datasets_metadata.html
	invenio_opendata/base/templates/records/CMS-Derived-Datasets_metadata.html
	invenio_opendata/base/templates/records/files_base.html
	invenio_opendata/base/templates/records/macros.html
	invenio_opendata/base/templates/records/metadata_base.html
fixtures: ALICE collection description updates

* Updates ALICE collection descriptions.  (closes #353)

Co-authored-by: Mihaela Gheata <mihaela.gheata@cern.ch>
Signed-off-by: Tibor Simko <tibor.simko@cern.ch>
templates: fix merge conflict left-over

* Fixes merge conflict leftover in a template introduced in
  990031546d9dd70bda921ca8a788ed82513925d8.  (PR #505)

* Also fixes indentation of the file.

Signed-off-by: Tibor Simko <tibor.simko@cern.ch>
CMS: update of copyright in `cms-tools-ana.xml`

* Updates copyright in `cms-tools-ana.xml`.
  (addresses #71) (PR #501)
CMS: fix case of "portal" case in `cms-tools-vm-image.xml`

* Fixes case of "portal" in "CERN Open Data Portal" in
  `cms-tools-vm-image.xml`.  (PR #510)
records: various template upgrades

* adds “Citation recommendation” to records with DOI
* fixes “Characteristics” section
* “Download file index” button-text for “txt” and “json” files (closes
* fixes “TB bytes” issue
CMS: immediate activate event display preview

* (closes #520)
ATLAS: descriptive text for external resources

* Adds descriptive text to `atlas-external-resources.xml`.
  (closes #487) (PR #523)
ATLAS: derived dataset descriptions

* Amends descriptions in `atlas-derived-datasets.xml`.
  (closes #485) (PR #524)
UI: new updated homepage proposal
search: facet fix

* fixes javascript errors for facets